LibGL: Implement glIsEnabled()

Userland/Libraries/LibGL/GL/gl.h

@@ -371,6 +371,7 @@ GLAPI void glVertex4sv(const GLshort* v);
 GLAPI void glViewport(GLint x, GLint y, GLsizei width, GLsizei height);
 GLAPI void glEnable(GLenum cap);
 GLAPI void glDisable(GLenum cap);
+GLAPI GLboolean glIsEnabled(GLenum cap);
 GLAPI void glCullFace(GLenum mode);
 GLAPI void glFrontFace(GLenum mode);
 GLAPI GLuint glGenLists(GLsizei range);

Userland/Libraries/LibGL/GLContext.h

@@ -42,6 +42,7 @@ public:
     virtual void gl_viewport(GLint x, GLint y, GLsizei width, GLsizei height) = 0;
     virtual void gl_enable(GLenum) = 0;
     virtual void gl_disable(GLenum) = 0;
+    virtual GLboolean gl_is_enabled(GLenum) = 0;
     virtual void gl_front_face(GLenum) = 0;
     virtual void gl_cull_face(GLenum) = 0;
     virtual GLuint gl_gen_lists(GLsizei range) = 0;

Userland/Libraries/LibGL/GLUtils.cpp

@@ -20,6 +20,11 @@ void glDisable(GLenum cap)
     g_gl_context->gl_disable(cap);
 }
 
+GLboolean glIsEnabled(GLenum cap)
+{
+    return g_gl_context->gl_is_enabled(cap);
+}
+
 void glFrontFace(GLenum mode)
 {
     g_gl_context->gl_front_face(mode);

Userland/Libraries/LibGL/SoftwareGLContext.cpp

@@ -597,6 +597,28 @@ void SoftwareGLContext::gl_disable(GLenum capability)
         m_rasterizer.set_options(rasterizer_options);
 }
 
+GLboolean SoftwareGLContext::gl_is_enabled(GLenum capability)
+{
+    RETURN_VALUE_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION, 0);
+
+    auto rasterizer_options = m_rasterizer.options();
+
+    switch (capability) {
+    case GL_CULL_FACE:
+        return m_cull_faces;
+    case GL_DEPTH_TEST:
+        return m_depth_test_enabled;
+    case GL_BLEND:
+        return m_blend_enabled;
+    case GL_ALPHA_TEST:
+        return m_alpha_test_enabled;
+    case GL_FOG:
+        return rasterizer_options.fog_enabled;
+    }
+
+    RETURN_VALUE_WITH_ERROR_IF(true, GL_INVALID_ENUM, 0);
+}
+
 void SoftwareGLContext::gl_gen_textures(GLsizei n, GLuint* textures)
 {
     RETURN_WITH_ERROR_IF(n < 0, GL_INVALID_VALUE);

Userland/Libraries/LibGL/SoftwareGLContext.h

@@ -52,6 +52,7 @@ public:
     virtual void gl_viewport(GLint x, GLint y, GLsizei width, GLsizei height) override;
     virtual void gl_enable(GLenum) override;
     virtual void gl_disable(GLenum) override;
+    virtual GLboolean gl_is_enabled(GLenum) override;
     virtual void gl_front_face(GLenum) override;
     virtual void gl_cull_face(GLenum) override;
     virtual GLuint gl_gen_lists(GLsizei range) override;