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Backends: GL3: Fix compile for < 3.2 bindings where glDrawElementsBaseVertex is not available. (#2866, #2852)

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dawid 2019-10-25 11:40:50 +02:00 committed by omar
parent 9b323a7ebf
commit 4d0c88e9e6
1 changed files with 22 additions and 7 deletions
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29
examples/imgui_impl_opengl3.cpp
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@ -120,14 +120,15 @@
#endif
// Desktop GL has glDrawElementsBaseVertex() which GL ES and WebGL don't have.
#if defined(IMGUI_IMPL_OPENGL_ES2) || defined(IMGUI_IMPL_OPENGL_ES3)
#define IMGUI_IMPL_OPENGL_HAS_DRAW_WITH_BASE_VERTEX 0
#if defined(IMGUI_IMPL_OPENGL_ES2) || defined(IMGUI_IMPL_OPENGL_ES3) || !defined(GL_VERSION_3_2)
#define IMGUI_IMPL_OPENGL_MAY_HAVE_DRAW_WITH_BASE_VERTEX 0
#else
#define IMGUI_IMPL_OPENGL_HAS_DRAW_WITH_BASE_VERTEX 1
#define IMGUI_IMPL_OPENGL_MAY_HAVE_DRAW_WITH_BASE_VERTEX 1
#endif
// OpenGL Data
static char g_GlslVersionString[32] = "";
static GLuint g_GlVersion = 0;
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
@ -137,11 +138,22 @@ static unsigned int g_VboHandle = 0, g_ElementsHandle = 0;
// Functions
bool ImGui_ImplOpenGL3_Init(const char* glsl_version)
{
// query for GL version
#if !defined(IMGUI_IMPL_OPENGL_ES2)
GLint major, minor;
glGetIntegerv (GL_MAJOR_VERSION, &major);
glGetIntegerv (GL_MINOR_VERSION, &minor);
g_GlVersion = major * 1000 + minor;
#else
g_GlVersion = 2000; // GLES 2
#endif
// Setup back-end capabilities flags
ImGuiIO& io = ImGui::GetIO();
io.BackendRendererName = "imgui_impl_opengl3";
#if IMGUI_IMPL_OPENGL_HAS_DRAW_WITH_BASE_VERTEX
io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset; // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
#if IMGUI_IMPL_OPENGL_MAY_HAVE_DRAW_WITH_BASE_VERTEX
if (g_GlVersion >= 3200)
io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset; // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
#endif
// Store GLSL version string so we can refer to it later in case we recreate shaders. Note: GLSL version is NOT the same as GL version. Leave this to NULL if unsure.
@ -344,8 +356,11 @@ void ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
// Bind texture, Draw
glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->TextureId);
#if IMGUI_IMPL_OPENGL_HAS_DRAW_WITH_BASE_VERTEX
glDrawElementsBaseVertex(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, (void*)(intptr_t)(pcmd->IdxOffset * sizeof(ImDrawIdx)), (GLint)pcmd->VtxOffset);
#if IMGUI_IMPL_OPENGL_MAY_HAVE_DRAW_WITH_BASE_VERTEX
if (g_GlVersion >= 3200)
glDrawElementsBaseVertex(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, (void*)(intptr_t)(pcmd->IdxOffset * sizeof(ImDrawIdx)), (GLint)pcmd->VtxOffset);
else
glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, (void*)(intptr_t)(pcmd->IdxOffset * sizeof(ImDrawIdx)));
#else
glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, (void*)(intptr_t)(pcmd->IdxOffset * sizeof(ImDrawIdx)));
#endif