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Use OpenGL2 glStencilOpSeparate() for shadows, if available

Browse source 
can be enabled/disabled with the r_useStencilOpSeparate for comparisons

(like Z-Fail, this doesn't really seem to make a difference on my main
 machine, neither on my RPi4)

Partly based on Pat Raynor's Code:
2933cb5545/neo/renderer/draw_stencilshadow.cpp
This commit is contained in:
Daniel Gibson 2019-11-03 02:58:21 +01:00
parent aeb03cc4e4
commit f24f18a61e
3 changed files with 86 additions and 38 deletions
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14
neo/renderer/RenderSystem_init.cpp
View file

@ -227,7 +227,7 @@ idCVar r_debugRenderToTexture( "r_debugRenderToTexture", "0", CVAR_RENDERER | CV
idCVar r_scaleMenusTo43( "r_scaleMenusTo43", "1", CVAR_RENDERER | CVAR_ARCHIVE | CVAR_BOOL, "Scale menus, fullscreen videos and PDA to 4:3 aspect ratio" );
// DG: the fscking patent has finally expired
idCVar r_useCarmacksReverse( "r_useCarmacksReverse", "1", CVAR_RENDERER | CVAR_ARCHIVE | CVAR_BOOL, "Use Z-Fail (Carmack's Reverse) when rendering shadows" );
idCVar r_useStencilOpSeparate( "r_useStencilOpSeparate", "1", CVAR_RENDERER | CVAR_ARCHIVE | CVAR_BOOL, "Use glStencilOpSeparate() (if available) when rendering shadows" );
// define qgl functions
#define QGLPROC(name, rettype, args) rettype (APIENTRYP q##name) args;
@ -275,6 +275,9 @@ PFNGLPROGRAMLOCALPARAMETER4FVARBPROC qglProgramLocalParameter4fvARB;
// GL_EXT_depth_bounds_test
PFNGLDEPTHBOUNDSEXTPROC qglDepthBoundsEXT;
// DG: couldn't find any extension for this, it's supported in GL2.0 and newer, incl OpenGL ES2.0
PFNGLSTENCILOPSEPARATEPROC qglStencilOpSeparate;
/*
=================
R_CheckExtension
@ -393,6 +396,15 @@ static void R_CheckPortableExtensions( void ) {
if ( glConfig.twoSidedStencilAvailable )
qglActiveStencilFaceEXT = (PFNGLACTIVESTENCILFACEEXTPROC)GLimp_ExtensionPointer( "glActiveStencilFaceEXT" );
if( glConfig.glVersion >= 2.0) {
common->Printf( "... got GL2.0+ glStencilOpSeparate()\n" );
qglStencilOpSeparate = (PFNGLSTENCILOPSEPARATEPROC)GLimp_ExtensionPointer( "glStencilOpSeparate" );
} else {
// TODO: there was an extension by ATI providing glStencilOpSeparateATI - do we care?
common->Printf( "... don't have GL2.0+ glStencilOpSeparate()\n" );
qglStencilOpSeparate = nullptr;
}
// ARB_vertex_buffer_object
glConfig.ARBVertexBufferObjectAvailable = R_CheckExtension( "GL_ARB_vertex_buffer_object" );
if(glConfig.ARBVertexBufferObjectAvailable) {

107
neo/renderer/draw_common.cpp
View file

@ -32,7 +32,7 @@ If you have questions concerning this license or the applicable additional terms
#include "renderer/tr_local.h"
extern idCVar r_useCarmacksReverse;
extern idCVar r_useStencilOpSeparate;
/*
=====================
RB_BakeTextureMatrixIntoTexgen
@ -1142,45 +1142,40 @@ static void RB_T_Shadow( const drawSurf_t *surf ) {
return;
}
if( !r_useCarmacksReverse.GetBool() ) { // LEITH: the original patent free "preload" code
// DG: that bloody patent on depth-fail stencil shadows has finally expired on 2019-10-13,
// so use them (see https://patents.google.com/patent/US6384822B1/en for expiration status)
bool useStencilOpSeperate = r_useStencilOpSeparate.GetBool() && qglStencilOpSeparate != nullptr;
if( !r_useCarmacksReverse.GetBool() ) {
if( useStencilOpSeperate ) {
// not using z-fail, but using qglStencilOpSeparate()
GLenum firstFace = backEnd.viewDef->isMirror ? GL_FRONT : GL_BACK;
GLenum secondFace = backEnd.viewDef->isMirror ? GL_BACK : GL_FRONT;
GL_Cull( CT_TWO_SIDED );
if ( !external ) {
qglStencilOpSeparate( firstFace, GL_KEEP, tr.stencilDecr, tr.stencilDecr );
qglStencilOpSeparate( secondFace, GL_KEEP, tr.stencilIncr, tr.stencilIncr );
RB_DrawShadowElementsWithCounters( tri, numIndexes );
}
qglStencilOpSeparate( firstFace, GL_KEEP, GL_KEEP, tr.stencilIncr );
qglStencilOpSeparate( secondFace, GL_KEEP, GL_KEEP, tr.stencilDecr );
// patent-free work around
if ( !external ) {
// "preload" the stencil buffer with the number of volumes
// that get clipped by the near or far clip plane
qglStencilOp( GL_KEEP, tr.stencilDecr, tr.stencilDecr );
GL_Cull( CT_FRONT_SIDED );
RB_DrawShadowElementsWithCounters( tri, numIndexes );
qglStencilOp( GL_KEEP, tr.stencilIncr, tr.stencilIncr );
GL_Cull( CT_BACK_SIDED );
RB_DrawShadowElementsWithCounters( tri, numIndexes );
}
// traditional depth-pass stencil shadows
qglStencilOp( GL_KEEP, GL_KEEP, tr.stencilIncr );
GL_Cull( CT_FRONT_SIDED );
RB_DrawShadowElementsWithCounters( tri, numIndexes );
} else { // DG: this is the original code:
// patent-free work around
if ( !external ) {
// "preload" the stencil buffer with the number of volumes
// that get clipped by the near or far clip plane
qglStencilOp( GL_KEEP, tr.stencilDecr, tr.stencilDecr );
GL_Cull( CT_FRONT_SIDED );
RB_DrawShadowElementsWithCounters( tri, numIndexes );
qglStencilOp( GL_KEEP, tr.stencilIncr, tr.stencilIncr );
GL_Cull( CT_BACK_SIDED );
RB_DrawShadowElementsWithCounters( tri, numIndexes );
}
qglStencilOp( GL_KEEP, GL_KEEP, tr.stencilDecr );
GL_Cull( CT_BACK_SIDED );
RB_DrawShadowElementsWithCounters( tri, numIndexes );
} else { // LEITH: the (formerly patented) "Carmack's Reverse" code
// DG: that bloody patent on depth-fail stencil shadows has finally expired on 2019-10-13,
// so use them (see https://patents.google.com/patent/US6384822B1/en for expiration status)
// depth-fail/Z-Fail stencil shadows
if ( !external ) {
qglStencilOp( GL_KEEP, tr.stencilDecr, GL_KEEP );
GL_Cull( CT_FRONT_SIDED );
RB_DrawShadowElementsWithCounters( tri, numIndexes );
qglStencilOp( GL_KEEP, tr.stencilIncr, GL_KEEP );
GL_Cull( CT_BACK_SIDED );
RB_DrawShadowElementsWithCounters( tri, numIndexes );
}
// traditional depth-pass stencil shadows
else {
// traditional depth-pass stencil shadows
qglStencilOp( GL_KEEP, GL_KEEP, tr.stencilIncr );
GL_Cull( CT_FRONT_SIDED );
RB_DrawShadowElementsWithCounters( tri, numIndexes );
@ -1189,8 +1184,46 @@ static void RB_T_Shadow( const drawSurf_t *surf ) {
GL_Cull( CT_BACK_SIDED );
RB_DrawShadowElementsWithCounters( tri, numIndexes );
}
}
} else { // use the formerly patented "Carmack's Reverse" Z-Fail code
if( useStencilOpSeperate ) {
// Z-Fail with glStencilOpSeparate() which will reduce draw calls
GLenum firstFace = backEnd.viewDef->isMirror ? GL_FRONT : GL_BACK;
GLenum secondFace = backEnd.viewDef->isMirror ? GL_BACK : GL_FRONT;
if ( !external ) { // z-fail
qglStencilOpSeparate( firstFace, GL_KEEP, tr.stencilDecr, GL_KEEP );
qglStencilOpSeparate( secondFace, GL_KEEP, tr.stencilIncr, GL_KEEP );
} else { // depth-pass
qglStencilOpSeparate( firstFace, GL_KEEP, GL_KEEP, tr.stencilIncr );
qglStencilOpSeparate( secondFace, GL_KEEP, GL_KEEP, tr.stencilDecr );
}
GL_Cull( CT_TWO_SIDED );
RB_DrawShadowElementsWithCounters( tri, numIndexes );
} else { // Z-Fail without glStencilOpSeparate()
// LEITH: the (formerly patented) "Carmack's Reverse" code
// depth-fail/Z-Fail stencil shadows
if ( !external ) {
qglStencilOp( GL_KEEP, tr.stencilDecr, GL_KEEP );
GL_Cull( CT_FRONT_SIDED );
RB_DrawShadowElementsWithCounters( tri, numIndexes );
qglStencilOp( GL_KEEP, tr.stencilIncr, GL_KEEP );
GL_Cull( CT_BACK_SIDED );
RB_DrawShadowElementsWithCounters( tri, numIndexes );
}
// traditional depth-pass stencil shadows
else {
qglStencilOp( GL_KEEP, GL_KEEP, tr.stencilIncr );
GL_Cull( CT_FRONT_SIDED );
RB_DrawShadowElementsWithCounters( tri, numIndexes );
qglStencilOp( GL_KEEP, GL_KEEP, tr.stencilDecr );
GL_Cull( CT_BACK_SIDED );
RB_DrawShadowElementsWithCounters( tri, numIndexes );
}
}
}
}
/*

3
neo/renderer/qgl.h
View file

@ -95,6 +95,9 @@ extern void ( APIENTRY *qglColorTableEXT)( int, int, int, int, int, const void *
// EXT_stencil_two_side
extern PFNGLACTIVESTENCILFACEEXTPROC qglActiveStencilFaceEXT;
// DG: couldn't find any extension for this, it's supported in GL2.0 and newer, incl OpenGL ES2.0
extern PFNGLSTENCILOPSEPARATEPROC qglStencilOpSeparate;
// ARB_texture_compression
extern PFNGLCOMPRESSEDTEXIMAGE2DARBPROC qglCompressedTexImage2DARB;
extern PFNGLGETCOMPRESSEDTEXIMAGEARBPROC qglGetCompressedTexImageARB;