swung0x48/MobileGL
1
0
Fork 0
mirror of https://github.com/MobileGL-Dev/MobileGL synced 2026-09-09 04:38:30 +09:00
Code Issues Packages Projects Releases Wiki Activity

[Fix, Test] (RenderState, DirectGLES, MG_IntegrationTest): tell a deliberately empty scissor box apart from one that was never written

Browse Source
This commit is contained in:
swung0x48
2026-08-20 22:27:14 -04:00
parent 7480bf4490
commit cd07d42a47
5 changed files with 341 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files
MobileGL/MG_Backend/DirectGLES/DirectGLES.cpp
+24 -12
View File
@@ -2134,19 +2134,31 @@ namespace MobileGL::MG_Backend::DirectGLES {
if (tailSpanDirty) { // Scissor box. Resolved and shadowed like the viewport above, and
// for the same reason: what has to reach the driver is NOT simply the parameter
// field. (0,0,0,0) is where RenderStateParameters::ScissorBox starts and the only
// thing that ever writes it is glScissor, so that value means "the application has
// never called glScissor" - it is not a GL scissor box. GL's initial box is the
// whole window, which the frontend has no way to spell before a surface exists.
// The pre-resync code got away with pushing the field verbatim only by accident:
// the shadow held the same default, the field never compared unequal, and the ES
// context kept its own correct default. Under the forced full push that accident
// is gone, glScissor(0,0,0,0) shrinks the scissor to an EMPTY rectangle, and
// everything drawn with GL_SCISSOR_TEST enabled before the app's first glScissor
// is clipped away - Minecraft 26.2 keeps only its unscissored sky and hand and
// loses the terrain and the whole GUI.
// field. RenderStateParameters::ScissorBoxes starts all-zero, which means "the
// application has never called glScissor" - it is not a GL scissor box. GL's
// initial box is the whole window, which the frontend has no way to spell before a
// surface exists. The pre-resync code got away with pushing the field verbatim only
// by accident: the shadow held the same default, the field never compared unequal,
// and the ES context kept its own correct default. Under the forced full push that
// accident is gone, glScissor(0,0,0,0) shrinks the scissor to an EMPTY rectangle,
// and everything drawn with GL_SCISSOR_TEST enabled before the app's first
// glScissor is clipped away - Minecraft 26.2 keeps only its unscissored sky and
// hand and loses the terrain and the whole GUI.
//
// The condition is the WRITTEN FLAG, not the extent. An empty rectangle is a
// perfectly legal thing to ask for - glScissor(0,0,0,0) means "the scissor test
// rejects every fragment" - so testing `width <= 0 || height <= 0` substituted the
// whole surface for a deliberately empty box and inverted the request into "accept
// every fragment", no matter how many times the application had already called
// glScissor. KHR-GL43.viewport_array.scissor_zero_dimension is exactly that: all 16
// boxes zero-sized with the test enabled, requiring the draw to be clipped away
// entirely. Reading the flag preserves the Minecraft protection bit-for-bit - before
// the first glScissor the bit is clear and the surface size is still substituted -
// while an explicit empty box now reaches the driver verbatim. Negative extents
// cannot arrive here at all: all three entry points reject them with
// GL_INVALID_VALUE before storing (GL_RenderState.cpp's ValidateNonNegativeExtent).
IntVec4 backendScissorBox = parameters.ScissorBoxes[0];
if (backendScissorBox.z() <= 0 || backendScissorBox.w() <= 0) {
if ((parameters.ScissorBoxWrittenMask & 1u) == 0) {
Int surfaceWidth = 0;
Int surfaceHeight = 0;
if (QueryCurrentSurfaceSize(surfaceWidth, surfaceHeight)) {