ImGui: Get rid of serializing GL calls in OpenGL renderer

Gives a 25% performance improvement on NVIDIA.
This commit is contained in:
Connor McLaughlin 2020-10-31 12:49:29 +10:00
parent b3c5c0f852
commit fdb770a596
1 changed files with 23 additions and 94 deletions

View File

@ -88,7 +88,7 @@ static GLuint g_FontTexture = 0;
static GLuint g_ShaderHandle = 0, g_VertHandle = 0, g_FragHandle = 0;
static int g_AttribLocationTex = 0, g_AttribLocationProjMtx = 0; // Uniforms location
static int g_AttribLocationVtxPos = 0, g_AttribLocationVtxUV = 0, g_AttribLocationVtxColor = 0; // Vertex attributes location
static unsigned int g_VboHandle = 0, g_ElementsHandle = 0;
static unsigned int g_VboHandle = 0, g_VaoHandle = 0, g_ElementsHandle = 0;
static bool g_IsGLES = false;
// Forward Declarations
@ -148,7 +148,7 @@ void ImGui_ImplOpenGL3_NewFrame()
ImGui_ImplOpenGL3_CreateDeviceObjects();
}
static void ImGui_ImplOpenGL3_SetupRenderState(ImDrawData* draw_data, int fb_width, int fb_height, GLuint vertex_array_object)
static void ImGui_ImplOpenGL3_SetupRenderState(ImDrawData* draw_data, int fb_width, int fb_height)
{
// Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, polygon fill
glEnable(GL_BLEND);
@ -183,20 +183,9 @@ static void ImGui_ImplOpenGL3_SetupRenderState(ImDrawData* draw_data, int fb_wid
glBindSampler(0, 0); // We use combined texture/sampler state. Applications using GL 3.3 may set that otherwise.
#endif
(void)vertex_array_object;
#ifndef IMGUI_IMPL_OPENGL_ES2
glBindVertexArray(vertex_array_object);
#endif
// Bind vertex/index buffers and setup attributes for ImDrawVert
glBindVertexArray(g_VaoHandle);
glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, g_ElementsHandle);
glEnableVertexAttribArray(g_AttribLocationVtxPos);
glEnableVertexAttribArray(g_AttribLocationVtxUV);
glEnableVertexAttribArray(g_AttribLocationVtxColor);
glVertexAttribPointer(g_AttribLocationVtxPos, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, pos));
glVertexAttribPointer(g_AttribLocationVtxUV, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, uv));
glVertexAttribPointer(g_AttribLocationVtxColor, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, col));
}
// OpenGL3 Render function.
@ -210,54 +199,7 @@ void ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
if (fb_width <= 0 || fb_height <= 0)
return;
// Backup GL state
GLenum last_active_texture; glGetIntegerv(GL_ACTIVE_TEXTURE, (GLint*)&last_active_texture);
glActiveTexture(GL_TEXTURE0);
GLint last_program; glGetIntegerv(GL_CURRENT_PROGRAM, &last_program);
GLint last_texture; glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
#ifdef GL_SAMPLER_BINDING
GLint last_sampler; glGetIntegerv(GL_SAMPLER_BINDING, &last_sampler);
#endif
GLint last_array_buffer; glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &last_array_buffer);
#ifndef IMGUI_IMPL_OPENGL_ES2
GLint last_vertex_array_object; glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &last_vertex_array_object);
#endif
#ifdef GL_POLYGON_MODE
GLint last_polygon_mode[2];
if (!g_IsGLES)
glGetIntegerv(GL_POLYGON_MODE, last_polygon_mode);
#endif
GLint last_viewport[4]; glGetIntegerv(GL_VIEWPORT, last_viewport);
GLint last_scissor_box[4]; glGetIntegerv(GL_SCISSOR_BOX, last_scissor_box);
GLenum last_blend_src_rgb; glGetIntegerv(GL_BLEND_SRC_RGB, (GLint*)&last_blend_src_rgb);
GLenum last_blend_dst_rgb; glGetIntegerv(GL_BLEND_DST_RGB, (GLint*)&last_blend_dst_rgb);
GLenum last_blend_src_alpha; glGetIntegerv(GL_BLEND_SRC_ALPHA, (GLint*)&last_blend_src_alpha);
GLenum last_blend_dst_alpha; glGetIntegerv(GL_BLEND_DST_ALPHA, (GLint*)&last_blend_dst_alpha);
GLenum last_blend_equation_rgb; glGetIntegerv(GL_BLEND_EQUATION_RGB, (GLint*)&last_blend_equation_rgb);
GLenum last_blend_equation_alpha; glGetIntegerv(GL_BLEND_EQUATION_ALPHA, (GLint*)&last_blend_equation_alpha);
GLboolean last_enable_blend = glIsEnabled(GL_BLEND);
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;
if (!g_IsGLES)
{
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)
// The renderer would actually work without any VAO bound, but then our VertexAttrib calls would overwrite the default one currently bound.
GLuint vertex_array_object = 0;
#ifndef IMGUI_IMPL_OPENGL_ES2
glGenVertexArrays(1, &vertex_array_object);
#endif
ImGui_ImplOpenGL3_SetupRenderState(draw_data, fb_width, fb_height, vertex_array_object);
ImGui_ImplOpenGL3_SetupRenderState(draw_data, fb_width, fb_height);
// Will project scissor/clipping rectangles into framebuffer space
ImVec2 clip_off = draw_data->DisplayPos; // (0,0) unless using multi-viewports
@ -279,7 +221,7 @@ void ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
// User callback, registered via ImDrawList::AddCallback()
// (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
ImGui_ImplOpenGL3_SetupRenderState(draw_data, fb_width, fb_height, vertex_array_object);
ImGui_ImplOpenGL3_SetupRenderState(draw_data, fb_width, fb_height);
else
pcmd->UserCallback(cmd_list, pcmd);
}
@ -295,10 +237,7 @@ 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);
@ -311,33 +250,6 @@ void ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
}
}
}
// Destroy the temporary VAO
#ifndef IMGUI_IMPL_OPENGL_ES2
glDeleteVertexArrays(1, &vertex_array_object);
#endif
// Restore modified GL state
glUseProgram(last_program);
glBindTexture(GL_TEXTURE_2D, last_texture);
glActiveTexture(last_active_texture);
#ifndef IMGUI_IMPL_OPENGL_ES2
glBindSampler(0, last_sampler);
glBindVertexArray(last_vertex_array_object);
#endif
glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
glBlendEquationSeparate(last_blend_equation_rgb, last_blend_equation_alpha);
glBlendFuncSeparate(last_blend_src_rgb, last_blend_dst_rgb, last_blend_src_alpha, last_blend_dst_alpha);
if (last_enable_blend) glEnable(GL_BLEND); else glDisable(GL_BLEND);
if (last_enable_cull_face) glEnable(GL_CULL_FACE); else glDisable(GL_CULL_FACE);
if (last_enable_depth_test) glEnable(GL_DEPTH_TEST); else glDisable(GL_DEPTH_TEST);
if (last_enable_scissor_test) glEnable(GL_SCISSOR_TEST); else glDisable(GL_SCISSOR_TEST);
#ifdef GL_POLYGON_MODE
if (!g_IsGLES)
glPolygonMode(GL_FRONT_AND_BACK, (GLenum)last_polygon_mode[0]);
#endif
glViewport(last_viewport[0], last_viewport[1], (GLsizei)last_viewport[2], (GLsizei)last_viewport[3]);
glScissor(last_scissor_box[0], last_scissor_box[1], (GLsizei)last_scissor_box[2], (GLsizei)last_scissor_box[3]);
}
bool ImGui_ImplOpenGL3_CreateFontsTexture()
@ -584,6 +496,22 @@ bool ImGui_ImplOpenGL3_CreateDeviceObjects()
glGenBuffers(1, &g_VboHandle);
glGenBuffers(1, &g_ElementsHandle);
glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
glBufferData(GL_ARRAY_BUFFER, sizeof(ImDrawVert), nullptr, GL_STREAM_DRAW);
glGenVertexArrays(1, &g_VaoHandle);
glBindVertexArray(g_VaoHandle);
glEnableVertexAttribArray(g_AttribLocationVtxPos);
glEnableVertexAttribArray(g_AttribLocationVtxUV);
glEnableVertexAttribArray(g_AttribLocationVtxColor);
glVertexAttribPointer(g_AttribLocationVtxPos, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert),
(GLvoid*)IM_OFFSETOF(ImDrawVert, pos));
glVertexAttribPointer(g_AttribLocationVtxUV, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert),
(GLvoid*)IM_OFFSETOF(ImDrawVert, uv));
glVertexAttribPointer(g_AttribLocationVtxColor, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert),
(GLvoid*)IM_OFFSETOF(ImDrawVert, col));
ImGui_ImplOpenGL3_CreateFontsTexture();
// Restore modified GL state
@ -598,6 +526,7 @@ bool ImGui_ImplOpenGL3_CreateDeviceObjects()
void ImGui_ImplOpenGL3_DestroyDeviceObjects()
{
if (g_VaoHandle) { glDeleteVertexArrays(1, &g_VaoHandle); g_VaoHandle = 0; }
if (g_VboHandle) { glDeleteBuffers(1, &g_VboHandle); g_VboHandle = 0; }
if (g_ElementsHandle) { glDeleteBuffers(1, &g_ElementsHandle); g_ElementsHandle = 0; }
if (g_ShaderHandle && g_VertHandle) { glDetachShader(g_ShaderHandle, g_VertHandle); }