LibGL: Add macro for error checking

This adds a macro `RETURN_WITH_ERROR_IF` to SoftwareGLContext
to remove a lot of noise from the interface implementation.

Userland/Libraries/LibGL/SoftwareGLContext.cpp

@@ -34,6 +34,18 @@ static constexpr size_t MATRIX_STACK_LIMIT = 1024;
             return;                                               \
     }
 
+#define RETURN_WITH_ERROR_IF(condition, error) \
+    if (condition) {                           \
+        m_error = error;                       \
+        return;                                \
+    }
+
+#define RETURN_VALUE_WITH_ERROR_IF(condition, error, return_value) \
+    if (condition) {                                               \
+        m_error = error;                                           \
+        return return_value;                                       \
+    }
+
 SoftwareGLContext::SoftwareGLContext(Gfx::Bitmap& frontbuffer)
     : m_frontbuffer(frontbuffer)
     , m_rasterizer(frontbuffer.size())
@@ -44,15 +56,8 @@ void SoftwareGLContext::gl_begin(GLenum mode)
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_begin, mode);
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
+    RETURN_WITH_ERROR_IF(mode < GL_TRIANGLES || mode > GL_POLYGON, GL_INVALID_ENUM);
-        return;
-    }
-
-    if (mode < GL_TRIANGLES || mode > GL_POLYGON) {
-        m_error = GL_INVALID_ENUM;
-        return;
-    }
 
     m_current_draw_mode = mode;
     m_in_draw_state = true; // Certain commands will now generate an error
@@ -63,15 +68,8 @@ void SoftwareGLContext::gl_clear(GLbitfield mask)
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_clear, mask);
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
+    RETURN_WITH_ERROR_IF(mask & ~(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT), GL_INVALID_ENUM);
-        return;
-    }
-
-    if (mask & ~(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)) {
-        m_error = GL_INVALID_ENUM;
-        return;
-    }
 
     if (mask & GL_COLOR_BUFFER_BIT)
         m_rasterizer.clear_color(m_clear_color);
@@ -86,10 +84,7 @@ void SoftwareGLContext::gl_clear_color(GLclampf red, GLclampf green, GLclampf bl
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_clear_color, red, green, blue, alpha);
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     m_clear_color = { red, green, blue, alpha };
     m_error = GL_NO_ERROR;
@@ -99,10 +94,7 @@ void SoftwareGLContext::gl_clear_depth(GLdouble depth)
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_clear_depth, depth);
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     m_clear_depth = depth;
     m_error = GL_NO_ERROR;
@@ -134,10 +126,7 @@ void SoftwareGLContext::gl_end()
     float scr_height = m_frontbuffer->height();
 
     // Make sure we had a `glBegin` before this call...
-    if (!m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(!m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     // Let's construct some triangles
     if (m_current_draw_mode == GL_TRIANGLES) {
@@ -185,8 +174,7 @@ void SoftwareGLContext::gl_end()
             triangle_list.append(triangle);
         }
     } else {
-        m_error = GL_INVALID_ENUM;
+        RETURN_WITH_ERROR_IF(true, GL_INVALID_ENUM);
-        return;
     }
 
     // Now let's transform each triangle and send that to the GPU
@@ -344,10 +332,7 @@ void SoftwareGLContext::gl_frustum(GLdouble left, GLdouble right, GLdouble botto
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_frustum, left, right, bottom, top, near_val, far_val);
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     // Let's do some math!
     // FIXME: Are we losing too much precision by doing this?
@@ -377,15 +362,8 @@ void SoftwareGLContext::gl_ortho(GLdouble left, GLdouble right, GLdouble bottom,
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_ortho, left, right, bottom, top, near_val, far_val);
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
+    RETURN_WITH_ERROR_IF(left == right || bottom == top || near_val == far_val, GL_INVALID_VALUE);
-        return;
-    }
-
-    if (left == right || bottom == top || near_val == far_val) {
-        m_error = GL_INVALID_VALUE;
-        return;
-    }
 
     auto rl = right - left;
     auto tb = top - bottom;
@@ -412,19 +390,15 @@ void SoftwareGLContext::gl_ortho(GLdouble left, GLdouble right, GLdouble bottom,
 
 GLenum SoftwareGLContext::gl_get_error()
 {
-    if (m_in_draw_state) {
+    if (m_in_draw_state)
         return GL_INVALID_OPERATION;
-    }
 
     return m_error;
 }
 
 GLubyte* SoftwareGLContext::gl_get_string(GLenum name)
 {
-    if (m_in_draw_state) {
+    RETURN_VALUE_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION, nullptr);
-        m_error = GL_INVALID_OPERATION;
-        return nullptr;
-    }
 
     switch (name) {
     case GL_VENDOR:
@@ -438,18 +412,14 @@ GLubyte* SoftwareGLContext::gl_get_string(GLenum name)
         break;
     }
 
-    m_error = GL_INVALID_ENUM;
+    RETURN_VALUE_WITH_ERROR_IF(true, GL_INVALID_ENUM, nullptr);
-    return nullptr;
 }
 
 void SoftwareGLContext::gl_load_identity()
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_load_identity);
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     if (m_current_matrix_mode == GL_PROJECTION)
         m_projection_matrix = FloatMatrix4x4::identity();
@@ -470,10 +440,7 @@ void SoftwareGLContext::gl_load_matrix(const FloatMatrix4x4& matrix)
             return;
     }
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     if (m_current_matrix_mode == GL_PROJECTION)
         m_projection_matrix = matrix;
@@ -489,15 +456,8 @@ void SoftwareGLContext::gl_matrix_mode(GLenum mode)
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_matrix_mode, mode);
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
+    RETURN_WITH_ERROR_IF(mode < GL_MODELVIEW || mode > GL_PROJECTION, GL_INVALID_ENUM);
-        return;
-    }
-
-    if (mode < GL_MODELVIEW || mode > GL_PROJECTION) {
-        m_error = GL_INVALID_ENUM;
-        return;
-    }
 
     m_current_matrix_mode = mode;
     m_error = GL_NO_ERROR;
@@ -507,26 +467,17 @@ void SoftwareGLContext::gl_push_matrix()
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_push_matrix);
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     dbgln_if(GL_DEBUG, "glPushMatrix(): Pushing matrix to the matrix stack (matrix_mode {})", m_current_matrix_mode);
 
     switch (m_current_matrix_mode) {
     case GL_PROJECTION:
-        if (m_projection_matrix_stack.size() >= MATRIX_STACK_LIMIT) {
+        RETURN_WITH_ERROR_IF(m_projection_matrix_stack.size() >= MATRIX_STACK_LIMIT, GL_STACK_OVERFLOW);
-            m_error = GL_STACK_OVERFLOW;
-            return;
-        }
         m_projection_matrix_stack.append(m_projection_matrix);
         break;
     case GL_MODELVIEW:
-        if (m_model_view_matrix_stack.size() >= MATRIX_STACK_LIMIT) {
+        RETURN_WITH_ERROR_IF(m_model_view_matrix_stack.size() >= MATRIX_STACK_LIMIT, GL_STACK_OVERFLOW);
-            m_error = GL_STACK_OVERFLOW;
-            return;
-        }
         m_model_view_matrix_stack.append(m_model_view_matrix);
         break;
     default:
@@ -541,27 +492,18 @@ void SoftwareGLContext::gl_pop_matrix()
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_pop_matrix);
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     dbgln_if(GL_DEBUG, "glPopMatrix(): Popping matrix from matrix stack (matrix_mode = {})", m_current_matrix_mode);
 
     // FIXME: Make sure stack::top() doesn't cause any  nasty issues if it's empty (that could result in a lockup/hang)
     switch (m_current_matrix_mode) {
     case GL_PROJECTION:
-        if (m_projection_matrix_stack.size() == 0) {
+        RETURN_WITH_ERROR_IF(m_projection_matrix_stack.size() == 0, GL_STACK_UNDERFLOW);
-            m_error = GL_STACK_UNDERFLOW;
-            return;
-        }
         m_projection_matrix = m_projection_matrix_stack.take_last();
         break;
     case GL_MODELVIEW:
-        if (m_model_view_matrix_stack.size() == 0) {
+        RETURN_WITH_ERROR_IF(m_model_view_matrix_stack.size() == 0, GL_STACK_UNDERFLOW);
-            m_error = GL_STACK_UNDERFLOW;
-            return;
-        }
         m_model_view_matrix = m_model_view_matrix_stack.take_last();
         break;
     default:
@@ -576,10 +518,7 @@ void SoftwareGLContext::gl_rotate(GLdouble angle, GLdouble x, GLdouble y, GLdoub
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_rotate, angle, x, y, z);
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     FloatVector3 axis = { (float)x, (float)y, (float)z };
     axis.normalize();
@@ -597,10 +536,7 @@ void SoftwareGLContext::gl_scale(GLdouble x, GLdouble y, GLdouble z)
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_scale, x, y, z);
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     if (m_current_matrix_mode == GL_MODELVIEW) {
         m_model_view_matrix = m_model_view_matrix * Gfx::scale_matrix(FloatVector3 { static_cast<float>(x), static_cast<float>(y), static_cast<float>(z) });
@@ -615,10 +551,7 @@ void SoftwareGLContext::gl_translate(GLdouble x, GLdouble y, GLdouble z)
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_translate, x, y, z);
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     if (m_current_matrix_mode == GL_MODELVIEW) {
         m_model_view_matrix = m_model_view_matrix * Gfx::translation_matrix(FloatVector3 { (float)x, (float)y, (float)z });
@@ -668,10 +601,7 @@ void SoftwareGLContext::gl_viewport(GLint x, GLint y, GLsizei width, GLsizei hei
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_viewport, x, y, width, height);
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     (void)(x);
     (void)(y);
@@ -684,10 +614,7 @@ void SoftwareGLContext::gl_enable(GLenum capability)
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_enable, capability);
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     auto rasterizer_options = m_rasterizer.options();
     bool update_rasterizer_options = false;
@@ -712,8 +639,7 @@ void SoftwareGLContext::gl_enable(GLenum capability)
         update_rasterizer_options = true;
         break;
     default:
-        m_error = GL_INVALID_ENUM;
+        RETURN_WITH_ERROR_IF(true, GL_INVALID_ENUM);
-        break;
     }
 
     if (update_rasterizer_options)
@@ -724,10 +650,7 @@ void SoftwareGLContext::gl_disable(GLenum capability)
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_disable, capability);
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     auto rasterizer_options = m_rasterizer.options();
     bool update_rasterizer_options = false;
@@ -752,8 +675,7 @@ void SoftwareGLContext::gl_disable(GLenum capability)
         update_rasterizer_options = false;
         break;
     default:
-        m_error = GL_INVALID_ENUM;
+        RETURN_WITH_ERROR_IF(true, GL_INVALID_ENUM);
-        break;
     }
 
     if (update_rasterizer_options)
@@ -762,15 +684,8 @@ void SoftwareGLContext::gl_disable(GLenum capability)
 
 void SoftwareGLContext::gl_gen_textures(GLsizei n, GLuint* textures)
 {
-    if (n < 0) {
+    RETURN_WITH_ERROR_IF(n < 0, GL_INVALID_VALUE);
-        m_error = GL_INVALID_VALUE;
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        return;
-    }
-
-    if (m_in_draw_state) {
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     m_name_allocator.allocate(n, textures);
 
@@ -784,15 +699,8 @@ void SoftwareGLContext::gl_gen_textures(GLsizei n, GLuint* textures)
 
 void SoftwareGLContext::gl_delete_textures(GLsizei n, const GLuint* textures)
 {
-    if (n < 0) {
+    RETURN_WITH_ERROR_IF(n < 0, GL_INVALID_VALUE);
-        m_error = GL_INVALID_VALUE;
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        return;
-    }
-
-    if (m_in_draw_state) {
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     m_name_allocator.free(n, textures);
 
@@ -806,47 +714,18 @@ void SoftwareGLContext::gl_delete_textures(GLsizei n, const GLuint* textures)
 
 void SoftwareGLContext::gl_tex_image_2d(GLenum target, GLint level, GLint internal_format, GLsizei width, GLsizei height, GLint border, GLenum format, GLenum type, const GLvoid* data)
 {
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     // We only support GL_TEXTURE_2D for now
-    if (target != GL_TEXTURE_2D) {
+    RETURN_WITH_ERROR_IF(target != GL_TEXTURE_2D, GL_INVALID_ENUM);
-        m_error = GL_INVALID_ENUM;
-        return;
-    }
 
     // We only support symbolic constants for now
-    if (!(internal_format == GL_RGB || internal_format == GL_RGBA)) {
+    RETURN_WITH_ERROR_IF(!(internal_format == GL_RGB || internal_format == GL_RGBA), GL_INVALID_ENUM);
-        m_error = GL_INVALID_VALUE;
+    RETURN_WITH_ERROR_IF(type != GL_UNSIGNED_BYTE, GL_INVALID_VALUE);
-        return;
+    RETURN_WITH_ERROR_IF(level < 0 || level > Texture::LOG2_MAX_TEXTURE_SIZE, GL_INVALID_VALUE);
-    }
+    RETURN_WITH_ERROR_IF(width < 0 || height < 0 || width > (2 + Texture::MAX_TEXTURE_SIZE) || height > (2 + Texture::MAX_TEXTURE_SIZE), GL_INVALID_VALUE);
-
+    RETURN_WITH_ERROR_IF((width & 2) != 0 || (height & 2) != 0, GL_INVALID_VALUE);
-    if (type != GL_UNSIGNED_BYTE) {
+    RETURN_WITH_ERROR_IF(border < 0 || border > 1, GL_INVALID_VALUE);
-        m_error = GL_INVALID_VALUE;
-        return;
-    }
-
-    if (level < 0 || level > Texture::LOG2_MAX_TEXTURE_SIZE) {
-        m_error = GL_INVALID_VALUE;
-        return;
-    }
-
-    if (width < 0 || height < 0 || width > (2 + Texture::MAX_TEXTURE_SIZE) || height > (2 + Texture::MAX_TEXTURE_SIZE)) {
-        m_error = GL_INVALID_VALUE;
-        return;
-    }
-
-    if ((width & 2) != 0 || (height & 2) != 0) {
-        m_error = GL_INVALID_VALUE;
-        return;
-    }
-
-    if (border < 0 || border > 1) {
-        m_error = GL_INVALID_VALUE;
-        return;
-    }
 
     // TODO: Load texture from the currently active texture unit
     // This is to test the functionality of texture data upload
@@ -857,10 +736,7 @@ void SoftwareGLContext::gl_front_face(GLenum face)
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_front_face, face);
 
-    if (face < GL_CW || face > GL_CCW) {
+    RETURN_WITH_ERROR_IF(face < GL_CW || face > GL_CCW, GL_INVALID_ENUM);
-        m_error = GL_INVALID_ENUM;
-        return;
-    }
 
     m_front_face = face;
 }
@@ -869,24 +745,15 @@ void SoftwareGLContext::gl_cull_face(GLenum cull_mode)
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_cull_face, cull_mode);
 
-    if (cull_mode < GL_FRONT || cull_mode > GL_FRONT_AND_BACK) {
+    RETURN_WITH_ERROR_IF(cull_mode < GL_FRONT || cull_mode > GL_FRONT_AND_BACK, GL_INVALID_ENUM);
-        m_error = GL_INVALID_ENUM;
-        return;
-    }
 
     m_culled_sides = cull_mode;
 }
 
 GLuint SoftwareGLContext::gl_gen_lists(GLsizei range)
 {
-    if (range <= 0) {
+    RETURN_VALUE_WITH_ERROR_IF(range <= 0, GL_INVALID_VALUE, 0);
-        m_error = GL_INVALID_VALUE;
+    RETURN_VALUE_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION, 0);
-        return 0;
-    }
-    if (m_in_draw_state) {
-        m_error = GL_INVALID_OPERATION;
-        return 0;
-    }
 
     auto initial_entry = m_listings.size();
     m_listings.resize(range + initial_entry);
@@ -932,14 +799,8 @@ void SoftwareGLContext::gl_delete_lists(GLuint list, GLsizei range)
 
 void SoftwareGLContext::gl_end_list()
 {
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
+    RETURN_WITH_ERROR_IF(!m_current_listing_index.has_value(), GL_INVALID_OPERATION);
-        return;
-    }
-    if (!m_current_listing_index.has_value()) {
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     m_listings[m_current_listing_index->index] = move(m_current_listing_index->listing);
     m_current_listing_index.clear();
@@ -947,22 +808,10 @@ void SoftwareGLContext::gl_end_list()
 
 void SoftwareGLContext::gl_new_list(GLuint list, GLenum mode)
 {
-    if (list == 0) {
+    RETURN_WITH_ERROR_IF(list == 0, GL_INVALID_VALUE);
-        m_error = GL_INVALID_VALUE;
+    RETURN_WITH_ERROR_IF(mode != GL_COMPILE && mode != GL_COMPILE_AND_EXECUTE, GL_INVALID_ENUM);
-        return;
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-    }
+    RETURN_WITH_ERROR_IF(m_current_listing_index.has_value(), GL_INVALID_OPERATION);
-    if (mode != GL_COMPILE && mode != GL_COMPILE_AND_EXECUTE) {
-        m_error = GL_INVALID_ENUM;
-        return;
-    }
-    if (m_in_draw_state) {
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
-    if (m_current_listing_index.has_value()) {
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     if (m_listings.size() < list)
         return;
@@ -972,20 +821,14 @@ void SoftwareGLContext::gl_new_list(GLuint list, GLenum mode)
 
 void SoftwareGLContext::gl_flush()
 {
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     // No-op since SoftwareGLContext is completely synchronous at the moment
 }
 
 void SoftwareGLContext::gl_finish()
 {
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     // No-op since SoftwareGLContext is completely synchronous at the moment
 }
@@ -994,15 +837,12 @@ void SoftwareGLContext::gl_blend_func(GLenum src_factor, GLenum dst_factor)
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_blend_func, src_factor, dst_factor);
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     // FIXME: The list of allowed enums differs between API versions
     // This was taken from the 2.0 spec on https://docs.gl/gl2/glBlendFunc
 
-    if (!(src_factor == GL_ZERO
+    RETURN_WITH_ERROR_IF(!(src_factor == GL_ZERO
                              || src_factor == GL_ONE
                              || src_factor == GL_SRC_COLOR
                              || src_factor == GL_ONE_MINUS_SRC_COLOR
@@ -1016,12 +856,10 @@ void SoftwareGLContext::gl_blend_func(GLenum src_factor, GLenum dst_factor)
                              || src_factor == GL_ONE_MINUS_CONSTANT_COLOR
                              || src_factor == GL_CONSTANT_ALPHA
                              || src_factor == GL_ONE_MINUS_CONSTANT_ALPHA
-            || src_factor == GL_SRC_ALPHA_SATURATE)) {
+                             || src_factor == GL_SRC_ALPHA_SATURATE),
-        m_error = GL_INVALID_ENUM;
+        GL_INVALID_ENUM);
-        return;
-    }
 
-    if (!(dst_factor == GL_ZERO
+    RETURN_WITH_ERROR_IF(!(dst_factor == GL_ZERO
                              || dst_factor == GL_ONE
                              || dst_factor == GL_SRC_COLOR
                              || dst_factor == GL_ONE_MINUS_SRC_COLOR
@@ -1034,10 +872,8 @@ void SoftwareGLContext::gl_blend_func(GLenum src_factor, GLenum dst_factor)
                              || dst_factor == GL_CONSTANT_COLOR
                              || dst_factor == GL_ONE_MINUS_CONSTANT_COLOR
                              || dst_factor == GL_CONSTANT_ALPHA
-            || dst_factor == GL_ONE_MINUS_CONSTANT_ALPHA)) {
+                             || dst_factor == GL_ONE_MINUS_CONSTANT_ALPHA),
-        m_error = GL_INVALID_ENUM;
+        GL_INVALID_ENUM);
-        return;
-    }
 
     m_blend_source_factor = src_factor;
     m_blend_destination_factor = dst_factor;
@@ -1052,15 +888,8 @@ void SoftwareGLContext::gl_shade_model(GLenum mode)
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_shade_model, mode);
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
+    RETURN_WITH_ERROR_IF(mode != GL_FLAT && mode != GL_SMOOTH, GL_INVALID_ENUM);
-        return;
-    }
-
-    if (mode != GL_FLAT && mode != GL_SMOOTH) {
-        m_error = GL_INVALID_ENUM;
-        return;
-    }
 
     auto options = m_rasterizer.options();
     options.shade_smooth = (mode == GL_SMOOTH);
@@ -1071,15 +900,8 @@ void SoftwareGLContext::gl_alpha_func(GLenum func, GLclampf ref)
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_alpha_func, func, ref);
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
+    RETURN_WITH_ERROR_IF(func < GL_NEVER || func > GL_ALWAYS, GL_INVALID_ENUM);
-        return;
-    }
-
-    if (func < GL_NEVER || func > GL_ALWAYS) {
-        m_error = GL_INVALID_ENUM;
-        return;
-    }
 
     m_alpha_test_func = func;
     m_alpha_test_ref_value = ref;
@@ -1094,28 +916,21 @@ void SoftwareGLContext::gl_hint(GLenum target, GLenum mode)
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_hint, target, mode);
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
-    if (target != GL_PERSPECTIVE_CORRECTION_HINT
+    RETURN_WITH_ERROR_IF(target != GL_PERSPECTIVE_CORRECTION_HINT
             && target != GL_POINT_SMOOTH_HINT
             && target != GL_LINE_SMOOTH_HINT
             && target != GL_POLYGON_SMOOTH_HINT
             && target != GL_FOG_HINT
             && target != GL_GENERATE_MIPMAP_HINT
-        && target != GL_TEXTURE_COMPRESSION_HINT) {
+            && target != GL_TEXTURE_COMPRESSION_HINT,
-        m_error = GL_INVALID_ENUM;
+        GL_INVALID_ENUM);
-        return;
-    }
 
-    if (mode != GL_DONT_CARE
+    RETURN_WITH_ERROR_IF(mode != GL_DONT_CARE
             && mode != GL_FASTEST
-        && mode != GL_NICEST) {
+            && mode != GL_NICEST,
-        m_error = GL_INVALID_ENUM;
+        GL_INVALID_ENUM);
-        return;
-    }
 
     // According to the spec implementors are free to ignore glHint. So we do.
 }
@@ -1124,53 +939,42 @@ void SoftwareGLContext::gl_read_buffer(GLenum mode)
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_read_buffer, mode);
 
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
-        return;
-    }
 
     // FIXME: Also allow aux buffers GL_AUX0 through GL_AUX3 here
     // plus any aux buffer between 0 and GL_AUX_BUFFERS
-    if (mode != GL_FRONT_LEFT
+    RETURN_WITH_ERROR_IF(mode != GL_FRONT_LEFT
             && mode != GL_FRONT_RIGHT
             && mode != GL_BACK_LEFT
             && mode != GL_BACK_RIGHT
             && mode != GL_FRONT
             && mode != GL_BACK
             && mode != GL_LEFT
-        && mode != GL_RIGHT) {
+            && mode != GL_RIGHT,
-        m_error = GL_INVALID_ENUM;
+        GL_INVALID_ENUM);
-        return;
-    }
 
     // FIXME: We do not currently have aux buffers, so make it an invalid
     // operation to select anything but front or back buffers. Also we do
     // not allow selecting the stereoscopic RIGHT buffers since we do not
     // have them configured.
-    if (mode != GL_FRONT_LEFT
+    RETURN_WITH_ERROR_IF(mode != GL_FRONT_LEFT
             && mode != GL_FRONT
             && mode != GL_BACK_LEFT
             && mode != GL_BACK
             && mode != GL_FRONT
             && mode != GL_BACK
-        && mode != GL_LEFT) {
+            && mode != GL_LEFT,
-        m_error = GL_INVALID_OPERATION;
+        GL_INVALID_OPERATION);
-        return;
-    }
 
     m_current_read_buffer = mode;
 }
 
 void SoftwareGLContext::gl_read_pixels(GLint x, GLint y, GLsizei width, GLsizei height, GLenum format, GLenum type, GLvoid* pixels)
 {
-    if (m_in_draw_state) {
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
-        m_error = GL_INVALID_OPERATION;
+    RETURN_WITH_ERROR_IF(width < 0 || height < 0, GL_INVALID_VALUE);
-        return;
-    }
 
-    // Check for negative width/height omitted because GLsizei is unsigned in our implementation
+    RETURN_WITH_ERROR_IF(format != GL_COLOR_INDEX
-
-    if (format != GL_COLOR_INDEX
             && format != GL_STENCIL_INDEX
             && format != GL_DEPTH_COMPONENT
             && format != GL_RED
@@ -1180,12 +984,10 @@ void SoftwareGLContext::gl_read_pixels(GLint x, GLint y, GLsizei width, GLsizei
             && format != GL_RGB
             && format != GL_RGBA
             && format != GL_LUMINANCE
-        && format != GL_LUMINANCE_ALPHA) {
+            && format != GL_LUMINANCE_ALPHA,
-        m_error = GL_INVALID_ENUM;
+        GL_INVALID_ENUM);
-        return;
-    }
 
-    if (type != GL_UNSIGNED_BYTE
+    RETURN_WITH_ERROR_IF(type != GL_UNSIGNED_BYTE
             && type != GL_BYTE
             && type != GL_BITMAP
             && type != GL_UNSIGNED_SHORT
@@ -1193,35 +995,26 @@ void SoftwareGLContext::gl_read_pixels(GLint x, GLint y, GLsizei width, GLsizei
             && type != GL_BLUE
             && type != GL_UNSIGNED_INT
             && type != GL_INT
-        && type != GL_FLOAT) {
+            && type != GL_FLOAT,
-        m_error = GL_INVALID_ENUM;
+        GL_INVALID_ENUM);
-        return;
-    }
 
-    if (format == GL_COLOR_INDEX) {
     // FIXME: We only support RGBA buffers for now.
     // Once we add support for indexed color modes do the correct check here
-        m_error = GL_INVALID_OPERATION;
+    RETURN_WITH_ERROR_IF(format == GL_COLOR_INDEX, GL_INVALID_OPERATION);
-        return;
-    }
 
-    if (format == GL_STENCIL_INDEX) {
     // FIXME: We do not have stencil buffers yet
     // Once we add support for stencil buffers do the correct check here
-        m_error = GL_INVALID_OPERATION;
+    RETURN_WITH_ERROR_IF(format == GL_STENCIL_INDEX, GL_INVALID_OPERATION);
-        return;
-    }
 
     if (format == GL_DEPTH_COMPONENT) {
         // FIXME: This check needs to be a bit more sophisticated. Currently the buffers
         // are hardcoded. Once we add proper structures for them we need to correct this check
-        if (m_current_read_buffer == GL_FRONT
+
-            || m_current_read_buffer == GL_FRONT_LEFT
-            || m_current_read_buffer == GL_FRONT_RIGHT) {
         // Error because only back buffer has a depth buffer
-            m_error = GL_INVALID_OPERATION;
+        RETURN_WITH_ERROR_IF(m_current_read_buffer == GL_FRONT
-            return;
+                || m_current_read_buffer == GL_FRONT_LEFT
-        }
+                || m_current_read_buffer == GL_FRONT_RIGHT,
+            GL_INVALID_OPERATION);
     }
 
     // Some helper functions for converting float values to integer types