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Fix glClipControl(GL_UPPER_LEFT) handling in opengl3.

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This commit is contained in:
u3shit 2020-04-21 02:13:06 +02:00 committed by omar
parent c0283c1289
commit 528b12eb7a
2 changed files with 13 additions and 10 deletions
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2
docs/CHANGELOG.txt
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@ -44,6 +44,8 @@ Other Changes:
- TreeNode: Fixed bug where dragging a payload over a TreeNode() with either _OpenOnDoubleClick
or _OpenOnArrow would open the node. (#143)
- Backends: Win32: Support for #define NOGDI, won't try to call GetDeviceCaps(). (#3137, #2327)
- Backends: OpenGL: Fixed handling of GL 4.5+ glClipControl(GL_UPPER_LEFT) by inverting the
projection matrix top and bottom values. (#3143, #3146) [@u3shit]
-----------------------------------------------------------------------

21
examples/imgui_impl_opengl3.cpp
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@ -13,6 +13,7 @@
// CHANGELOG
// (minor and older changes stripped away, please see git history for details)
// 2020-04-21: OpenGL: Fixed handling of glClipControl(GL_UPPER_LEFT) by inverting projection matrix.
// 2020-04-12: OpenGL: Fixed context version check mistakenly testing for 4.0+ instead of 3.2+ to enable ImGuiBackendFlags_RendererHasVtxOffset.
// 2020-03-24: OpenGL: Added support for glbinding 2.x OpenGL loader.
// 2020-01-07: OpenGL: Added support for glbinding 3.x OpenGL loader.
@ -243,6 +244,14 @@ static void ImGui_ImplOpenGL3_SetupRenderState(ImDrawData* draw_data, int fb_wid
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
#endif
// Support for GL 4.5 rarely used glClipControl(GL_UPPER_LEFT)
bool clip_origin_lower_left = true;
#if defined(GL_CLIP_ORIGIN) && !defined(__APPLE__)
GLenum current_clip_origin = 0; glGetIntegerv(GL_CLIP_ORIGIN, (GLint*)&current_clip_origin);
if (current_clip_origin == GL_UPPER_LEFT)
clip_origin_lower_left = false;
#endif
// Setup viewport, orthographic projection matrix
// Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayPos is (0,0) for single viewport apps.
glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height);
@ -250,6 +259,7 @@ static void ImGui_ImplOpenGL3_SetupRenderState(ImDrawData* draw_data, int fb_wid
float R = draw_data->DisplayPos.x + draw_data->DisplaySize.x;
float T = draw_data->DisplayPos.y;
float B = draw_data->DisplayPos.y + draw_data->DisplaySize.y;
if (!clip_origin_lower_left) { float tmp = T; T = B; B = tmp; } // Swap top and bottom if origin is upper left
const float ortho_projection[4][4] =
{
{ 2.0f/(R-L), 0.0f, 0.0f, 0.0f },
@ -318,12 +328,6 @@ void ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
GLboolean last_enable_cull_face = glIsEnabled(GL_CULL_FACE);
GLboolean last_enable_depth_test = glIsEnabled(GL_DEPTH_TEST);
GLboolean last_enable_scissor_test = glIsEnabled(GL_SCISSOR_TEST);
bool clip_origin_lower_left = true;
#if defined(GL_CLIP_ORIGIN) && !defined(__APPLE__)
GLenum last_clip_origin = 0; glGetIntegerv(GL_CLIP_ORIGIN, (GLint*)&last_clip_origin); // Support for GL 4.5's glClipControl(GL_UPPER_LEFT)
if (last_clip_origin == GL_UPPER_LEFT)
clip_origin_lower_left = false;
#endif
// Setup desired GL state
// Recreate the VAO every time (this is to easily allow multiple GL contexts to be rendered to. VAO are not shared among GL contexts)
@ -371,10 +375,7 @@ void ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
if (clip_rect.x < fb_width && clip_rect.y < fb_height && clip_rect.z >= 0.0f && clip_rect.w >= 0.0f)
{
// Apply scissor/clipping rectangle
if (clip_origin_lower_left)
glScissor((int)clip_rect.x, (int)(fb_height - clip_rect.w), (int)(clip_rect.z - clip_rect.x), (int)(clip_rect.w - clip_rect.y));
else
glScissor((int)clip_rect.x, (int)clip_rect.y, (int)clip_rect.z, (int)clip_rect.w); // Support for GL 4.5 rarely used glClipControl(GL_UPPER_LEFT)
glScissor((int)clip_rect.x, (int)(fb_height - clip_rect.w), (int)(clip_rect.z - clip_rect.x), (int)(clip_rect.w - clip_rect.y));
// Bind texture, Draw
glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->TextureId);