LibGL: Immediately dereference vertex attribute data in display lists

According to the spec, pointers to client data need to be dereferenced
immediately when adding calls such as `glDrawElements` or
`glArrayElement` to a display list. We were trying to support display
lists for these calls but since they only invoke _other_ calls that also
support display lists, we can simply defer the display list
functionality to them.

This fixes the rendering of the ClassiCube port by cflip.

Tests/LibGL/TestRender.cpp

@@ -252,3 +252,29 @@ TEST_CASE(0008_test_pop_matrix_regression)
     context->present();
     expect_bitmap_equals_reference(context->frontbuffer(), "0008_test_pop_matrix_regression"sv);
 }
+
+TEST_CASE(0009_test_draw_elements_in_display_list)
+{
+    auto context = create_testing_context(64, 64);
+
+    glColor3f(0.f, 0.f, 1.f);
+    glEnableClientState(GL_VERTEX_ARRAY);
+
+    auto const list_index = glGenLists(1);
+    glNewList(list_index, GL_COMPILE);
+    float vertices[] = { 0.f, .5f, -.5f, -.5f, .5f, -.5f };
+    glVertexPointer(2, GL_FLOAT, 0, &vertices);
+    u8 indices[] = { 0, 1, 2 };
+    glDrawElements(GL_TRIANGLES, 3, GL_UNSIGNED_BYTE, &indices);
+    glEndList();
+
+    // Modifying an index here should not have an effect
+    indices[0] = 2;
+
+    glCallList(list_index);
+
+    EXPECT_EQ(glGetError(), 0u);
+
+    context->present();
+    expect_bitmap_equals_reference(context->frontbuffer(), "0009_test_draw_elements_in_display_list"sv);
+}

Userland/Libraries/LibGL/GLContext.h

@@ -441,8 +441,6 @@ private:
             decltype(&GLContext::gl_tex_parameter),
             decltype(&GLContext::gl_tex_parameterfv),
             decltype(&GLContext::gl_depth_mask),
-            decltype(&GLContext::gl_draw_arrays),
-            decltype(&GLContext::gl_draw_elements),
             decltype(&GLContext::gl_draw_pixels),
             decltype(&GLContext::gl_depth_range),
             decltype(&GLContext::gl_polygon_offset),
@@ -473,7 +471,6 @@ private:
             decltype(&GLContext::gl_color_material),
             decltype(&GLContext::gl_get_light),
             decltype(&GLContext::gl_clip_plane),
-            decltype(&GLContext::gl_array_element),
             decltype(&GLContext::gl_copy_tex_sub_image_2d),
             decltype(&GLContext::gl_point_size)>;
 

Userland/Libraries/LibGL/Vertex.cpp

@@ -14,7 +14,8 @@ namespace GL {
 
 void GLContext::gl_array_element(GLint i)
 {
-    APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_array_element, i);
+    // NOTE: This always dereferences data; display list support is deferred to the
+    //       individual vertex attribute calls such as `gl_color`, `gl_normal` etc.
     RETURN_WITH_ERROR_IF(i < 0, GL_INVALID_VALUE);
 
     // This is effectively the same as `gl_draw_elements`, except we only output a single
@@ -79,7 +80,8 @@ void GLContext::gl_color_pointer(GLint size, GLenum type, GLsizei stride, void c
 
 void GLContext::gl_draw_arrays(GLenum mode, GLint first, GLsizei count)
 {
-    APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_draw_arrays, mode, first, count);
+    // NOTE: This always dereferences data; display list support is deferred to the
+    //       individual vertex attribute calls such as `gl_color`, `gl_normal` etc.
     RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
 
     // FIXME: Some modes are still missing (GL_POINTS, GL_LINE_STRIP, GL_LINE_LOOP, GL_LINES)
@@ -129,7 +131,8 @@ void GLContext::gl_draw_arrays(GLenum mode, GLint first, GLsizei count)
 
 void GLContext::gl_draw_elements(GLenum mode, GLsizei count, GLenum type, void const* indices)
 {
-    APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_draw_elements, mode, count, type, indices);
+    // NOTE: This always dereferences data; display list support is deferred to the
+    //       individual vertex attribute calls such as `gl_color`, `gl_normal` etc.
     RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
 
     // FIXME: Some modes are still missing (GL_POINTS, GL_LINE_STRIP, GL_LINE_LOOP, GL_LINES)