LibGL: Implement glArrayElement

Userland/Libraries/LibGL/GL/gl.h

@@ -680,6 +680,7 @@ GLAPI void glRecti(GLint x1, GLint y1, GLint x2, GLint y2);
 GLAPI void glGetTexLevelParameteriv(GLenum target, GLint level, GLenum pname, GLint* params);
 GLAPI void glPointSize(GLfloat size);
 GLAPI void glClipPlane(GLenum plane, GLdouble const* equation);
+GLAPI void glArrayElement(GLint i);
 
 #ifdef __cplusplus
 }

Userland/Libraries/LibGL/GLContext.cpp

@@ -2308,6 +2308,41 @@ void GLContext::gl_draw_pixels(GLsizei width, GLsizei height, GLenum format, GLe
     }
 }
 
+void GLContext::gl_array_element(GLint i)
+{
+    APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_array_element, i);
+    RETURN_WITH_ERROR_IF(i < 0, GL_INVALID_VALUE);
+
+    // This is effectively the same as `gl_draw_elements`, except we only output a single
+    // vertex (this is done between a `gl_begin/end` call) that is to be rendered.
+    if (!m_client_side_vertex_array_enabled)
+        return;
+
+    if (m_client_side_color_array_enabled) {
+        float color[4] { 0, 0, 0, 1 };
+        read_from_vertex_attribute_pointer(m_client_color_pointer, i, color);
+        gl_color(color[0], color[1], color[2], color[3]);
+    }
+
+    for (size_t t = 0; t < m_client_tex_coord_pointer.size(); ++t) {
+        if (m_client_side_texture_coord_array_enabled[t]) {
+            float tex_coords[4] { 0, 0, 0, 0 };
+            read_from_vertex_attribute_pointer(m_client_tex_coord_pointer[t], i, tex_coords);
+            gl_multi_tex_coord(GL_TEXTURE0 + t, tex_coords[0], tex_coords[1], tex_coords[2], tex_coords[3]);
+        }
+    }
+
+    if (m_client_side_normal_array_enabled) {
+        float normal[3];
+        read_from_vertex_attribute_pointer(m_client_normal_pointer, i, normal);
+        gl_normal(normal[0], normal[1], normal[2]);
+    }
+
+    float vertex[4] { 0, 0, 0, 1 };
+    read_from_vertex_attribute_pointer(m_client_vertex_pointer, i, vertex);
+    gl_vertex(vertex[0], vertex[1], vertex[2], vertex[3]);
+}
+
 void GLContext::gl_depth_range(GLdouble min, GLdouble max)
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_depth_range, min, max);

Userland/Libraries/LibGL/GLContext.h

@@ -158,6 +158,7 @@ public:
     void gl_get_light(GLenum light, GLenum pname, void* params, GLenum type);
     void gl_get_material(GLenum face, GLenum pname, void* params, GLenum type);
     void gl_clip_plane(GLenum plane, GLdouble const* equation);
+    void gl_array_element(GLint i);
     void present();
 
 private:
@@ -400,7 +401,8 @@ private:
             decltype(&GLContext::gl_materialiv),
             decltype(&GLContext::gl_color_material),
             decltype(&GLContext::gl_get_light),
-            decltype(&GLContext::gl_clip_plane)>;
+            decltype(&GLContext::gl_clip_plane),
+            decltype(&GLContext::gl_array_element)>;
 
         using ExtraSavedArguments = Variant<
             FloatMatrix4x4>;

Userland/Libraries/LibGL/GLVertexArrays.cpp

@@ -33,3 +33,8 @@ void glDrawElements(GLenum mode, GLsizei count, GLenum type, void const* indices
 {
     g_gl_context->gl_draw_elements(mode, count, type, indices);
 }
+
+void glArrayElement(GLint i)
+{
+    g_gl_context->gl_array_element(i);
+}