fix scale issue with offsetmapping LOD due to calculated fractional steps count

[xonotic/darkplaces.git] / shader_glsl.h

diff --git a/shader_glsl.h b/shader_glsl.h
index f968e3eb852a5f4fc4dcf3718f7c012b190c0765..bb489c8f92ba1d234f9fd6fdaf5902c7b236b39a 100644 (file)
--- a/shader_glsl.h
+++ b/shader_glsl.h
@@ -726,8 +726,12 @@
 "      float i;\n"
 "      // distance-based LOD\n"
 "#ifdef USEOFFSETMAPPING_LOD\n"
-"      mediump float LODFactor = min(1.0, OffsetMapping_LodDistance / EyeVectorFogDepth.z);\n"
-"      mediump vec4 ScaleSteps = vec4(OffsetMapping_ScaleSteps.x, OffsetMapping_ScaleSteps.y * LODFactor, OffsetMapping_ScaleSteps.z / LODFactor, OffsetMapping_ScaleSteps.w * LODFactor);\n"
+"      //mediump float LODFactor = min(1.0, OffsetMapping_LodDistance / EyeVectorFogDepth.z);\n"
+"      //mediump vec4 ScaleSteps = vec4(OffsetMapping_ScaleSteps.x, OffsetMapping_ScaleSteps.y * LODFactor, OffsetMapping_ScaleSteps.z / LODFactor, OffsetMapping_ScaleSteps.w * LODFactor);\n"
+"      mediump float GuessLODFactor = min(1.0, OffsetMapping_LodDistance / EyeVectorFogDepth.z);\n"
+"      mediump float LODSteps = ceil(GuessLODFactor * OffsetMapping_ScaleSteps.y);\n"
+"      mediump float LODFactor = LODSteps / OffsetMapping_ScaleSteps.y;\n"
+"      mediump vec4 ScaleSteps = vec4(OffsetMapping_ScaleSteps.x, LODSteps, 1.0 / LODSteps, OffsetMapping_ScaleSteps.w * LODFactor);\n"
 "#else\n"
 "      #define ScaleSteps OffsetMapping_ScaleSteps\n"
 "#endif\n"