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[Fix] (MG_Backend/DirectGLES): GLES clamps glClearColor to [0,1], zeroing the -FLT_MAX MAX-blend identity; route out-of-range color clears through glClearBufferfv

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swung0x48
2026-07-17 11:45:55 -04:00
parent c30bd0fabb
commit a25d8ee0e7
1 changed files with 96 additions and 1 deletions
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MobileGL/MG_Backend/DirectGLES/DirectGLES.cpp
+96 -1
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@@ -1487,7 +1487,102 @@ namespace MobileGL::MG_Backend::DirectGLES {
BindCurrentFBO(FramebufferTarget::Draw);
g_GLESFuncs.glClear(mask);
// Debug-only diagnostics: is each offscreen clear complete and unscissored?
#if MOBILEGL_LOG_ACTIVE_LEVEL <= MOBILEGL_LOG_LEVEL_DEBUG
{
static int diagCount = 0;
GLint fboId = 0;
g_GLESFuncs.glGetIntegerv(GL_DRAW_FRAMEBUFFER_BINDING, &fboId);
if (fboId != 0 && diagCount++ < 900) {
GLint color0 = 0, depthName = 0, box[4] = {0};
GLboolean scissor = g_GLESFuncs.glIsEnabled(GL_SCISSOR_TEST);
GLboolean cmask[4] = {0};
GLfloat cc[4] = {0};
g_GLESFuncs.glGetFramebufferAttachmentParameteriv(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME, &color0);
g_GLESFuncs.glGetFramebufferAttachmentParameteriv(GL_DRAW_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME, &depthName);
g_GLESFuncs.glGetIntegerv(GL_SCISSOR_BOX, box);
g_GLESFuncs.glGetBooleanv(GL_COLOR_WRITEMASK, cmask);
g_GLESFuncs.glGetFloatv(GL_COLOR_CLEAR_VALUE, cc);
MGLOG_D("CLEAR fbo=%d color0=%d depth=%d mask=0x%x scissor=%d box=(%d,%d,%d,%d) cmask=%d%d%d%d cc=(%g,%g,%g,%g)",
fboId, color0, depthName, mask, (int)scissor, box[0], box[1], box[2], box[3], (int)cmask[0],
(int)cmask[1], (int)cmask[2], (int)cmask[3], cc[0], cc[1], cc[2], cc[3]);
}
}
#endif
// GLES clamps the glClearColor state to [0,1] (desktop GL keeps it unclamped
// for float color buffers). Minecraft's OIT clears its depth-bounds RGBA32F
// target to -FLT_MAX as the MAX-blend identity, so an out-of-range clear
// color must go through glClearBufferfv, which GLES does not clamp.
GLbitfield remainingMask = mask;
if ((mask & GL_COLOR_BUFFER_BIT) != 0) {
const FloatVec4& cc = MG_State::pGLContext->GetRenderStateParameters().ClearColor;
const Bool outOfRange = cc.x() < 0.f || cc.x() > 1.f || cc.y() < 0.f || cc.y() > 1.f || cc.z() < 0.f ||
cc.z() > 1.f || cc.w() < 0.f || cc.w() > 1.f;
GLint clearDrawFbo = 0;
g_GLESFuncs.glGetIntegerv(GL_DRAW_FRAMEBUFFER_BINDING, &clearDrawFbo);
if (outOfRange && clearDrawFbo != 0) {
const GLfloat value[4] = {cc.x(), cc.y(), cc.z(), cc.w()};
GLint maxDrawBuffers = 0;
GLint clearedCount = 0;
GLint firstDb = -1;
g_GLESFuncs.glGetIntegerv(GL_MAX_DRAW_BUFFERS, &maxDrawBuffers);
for (GLint i = 0; i < maxDrawBuffers; ++i) {
GLint db = GL_NONE;
g_GLESFuncs.glGetIntegerv(GL_DRAW_BUFFER0 + static_cast<GLenum>(i), &db);
if (i == 0) firstDb = db;
if (db != GL_NONE) {
g_GLESFuncs.glClearBufferfv(GL_COLOR, i, value);
++clearedCount;
}
}
remainingMask &= ~static_cast<GLbitfield>(GL_COLOR_BUFFER_BIT);
(void)clearedCount;
(void)firstDb;
// Debug-only diagnostics: verify the unclamped clear actually landed.
#if MOBILEGL_LOG_ACTIVE_LEVEL <= MOBILEGL_LOG_LEVEL_DEBUG
{
static int diagCount = 0;
if (diagCount++ < 20) {
const GLenum clrErr = g_GLESFuncs.glGetError();
GLint prevRead = 0, prevPbo = 0;
g_GLESFuncs.glGetIntegerv(GL_READ_FRAMEBUFFER_BINDING, &prevRead);
g_GLESFuncs.glGetIntegerv(GL_PIXEL_PACK_BUFFER_BINDING, &prevPbo);
g_GLESFuncs.glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
g_GLESFuncs.glBindFramebuffer(GL_READ_FRAMEBUFFER, (GLuint)clearDrawFbo);
GLint prevReadBuf = GL_COLOR_ATTACHMENT0;
g_GLESFuncs.glGetIntegerv(GL_READ_BUFFER, &prevReadBuf);
g_GLESFuncs.glReadBuffer(GL_COLOR_ATTACHMENT0);
GLfloat rb[4] = {0};
g_GLESFuncs.glReadPixels(100, 100, 1, 1, GL_RGBA, GL_FLOAT, rb);
const GLenum rbErr = g_GLESFuncs.glGetError();
const auto& feFbo =
MG_State::pGLContext->GetFramebufferBindingSlot(FramebufferTarget::Draw).GetBoundObject();
int feDb0 = -1, feDb1 = -1;
Uint feIdx = 0, feVer = 0;
if (feFbo) {
feIdx = feFbo->GetExternalIndex();
feVer = feFbo->GetObjectVersion();
feDb0 = (int)feFbo->GetDrawBuffers()[0];
feDb1 = (int)feFbo->GetDrawBuffers()[1];
}
MGLOG_D("CLEARV fbo=%d clrErr=0x%x rbErr=0x%x cc.x=%g cleared=%d firstDb=0x%x prevReadBuf=0x%x "
"feFbo=%u feVer=%u feDb=[%d,%d] stored=(%g,%g,%g,%g)",
clearDrawFbo, clrErr, rbErr, cc.x(), clearedCount, firstDb, prevReadBuf, feIdx, feVer,
feDb0, feDb1, rb[0], rb[1], rb[2], rb[3]);
g_GLESFuncs.glReadBuffer(static_cast<GLenum>(prevReadBuf));
g_GLESFuncs.glBindFramebuffer(GL_READ_FRAMEBUFFER, (GLuint)prevRead);
g_GLESFuncs.glBindBuffer(GL_PIXEL_PACK_BUFFER, (GLuint)prevPbo);
}
}
#endif
}
}
if (remainingMask != 0) {
g_GLESFuncs.glClear(remainingMask);
}
}
// GLES core supports only GL_PRIMITIVE_RESTART_FIXED_INDEX (fixed all-ones value). If the app