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Codechange: [OpenGL] Let OpenGL clear the pixel buffer if possible.

pull/8729/head
Michael Lutz 2021-01-17 00:42:14 +01:00
parent 94d8acb7d0
commit 86c309ea75
1 changed files with 15 additions and 4 deletions
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11
src/video/opengl.cpp
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@ -54,6 +54,7 @@ static PFNGLBINDBUFFERPROC _glBindBuffer;
static PFNGLBUFFERDATAPROC _glBufferData;
static PFNGLMAPBUFFERPROC _glMapBuffer;
static PFNGLUNMAPBUFFERPROC _glUnmapBuffer;
static PFNGLCLEARBUFFERSUBDATAPROC _glClearBufferSubData;
static PFNGLBUFFERSTORAGEPROC _glBufferStorage;
static PFNGLMAPBUFFERRANGEPROC _glMapBufferRange;
@ -209,6 +210,12 @@ static bool BindVBOExtension()
_glUnmapBuffer = (PFNGLUNMAPBUFFERPROC)GetOGLProcAddress("glUnmapBufferARB");
}
if (IsOpenGLVersionAtLeast(4, 3) || IsOpenGLExtensionSupported("GL_ARB_clear_buffer_object")) {
_glClearBufferSubData = (PFNGLCLEARBUFFERSUBDATAPROC)GetOGLProcAddress("glClearBufferSubData");
} else {
_glClearBufferSubData = nullptr;
}
return _glGenBuffers != nullptr && _glDeleteBuffers != nullptr && _glBindBuffer != nullptr && _glBufferData != nullptr && _glMapBuffer != nullptr && _glUnmapBuffer != nullptr;
}
@ -776,12 +783,16 @@ bool OpenGLBackend::Resize(int w, int h, bool force)
if (bpp == 32) {
/* Initialize backing store alpha to opaque for 32bpp modes. */
Colour black(0, 0, 0);
if (_glClearBufferSubData != nullptr) {
_glClearBufferSubData(GL_PIXEL_UNPACK_BUFFER, GL_RGBA8, 0, pitch * h * bpp / 8, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, &black.data);
} else {
uint32 *buf = (uint32 *)_glMapBuffer(GL_PIXEL_UNPACK_BUFFER, GL_READ_WRITE);
for (int i = 0; i < pitch * h; i++) {
*buf++ = black.data;
}
_glUnmapBuffer(GL_PIXEL_UNPACK_BUFFER);
}
}
_glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
_glActiveTexture(GL_TEXTURE0);