Fix glsl_restart with material system

src/engine/renderer/Material.cpp

@@ -1394,6 +1394,9 @@ void MaterialSystem::ProcessStage( drawSurf_t* drawSurf, shaderStage_t* pStage,
 	pStage->materialProcessor( &material, pStage, drawSurf );
 	pStage->paddedSize = material.shader->GetPaddedSize();
 
+	material.refStage = pStage;
+	material.refDrawSurf = *drawSurf;
+
 	std::vector<Material>& materials = materialPacks[materialPack].materials;
 	std::vector<Material>::iterator currentSearchIt = materials.begin();
 	std::vector<Material>::iterator materialIt;
@@ -1541,6 +1544,15 @@ void MaterialSystem::AddAllWorldSurfaces() {
 	generatingWorldCommandBuffer = false;
 }
 
+void MaterialSystem::GLSLRestart() {
+	for ( MaterialPack& materialPack : materialPacks ) {
+		for ( Material& material : materialPack.materials ) {
+			// We only really need to reset material.shader here
+			material.refStage->materialProcessor( &material, material.refStage, &material.refDrawSurf );
+		}
+	}
+}
+
 void MaterialSystem::AddStageTextures( drawSurf_t* drawSurf, const uint32_t stage, Material* material ) {
 	TextureData textureData;
 	const shaderStage_t* pStage = &drawSurf->shader->stages[stage];

src/engine/renderer/Material.h

@@ -85,6 +85,10 @@ struct Material {
 	GLuint program = 0;
 	GLShader* shader;
 
+	// Used only for glsl_restart
+	shaderStage_t* refStage;
+	drawSurf_t refDrawSurf;
+
 	int deformIndex;
 	bool tcGenEnvironment;
 	bool tcGen_Lightmap;
@@ -347,6 +351,8 @@ class MaterialSystem {
 
 	void AddAllWorldSurfaces();
 
+	void GLSLRestart();
+
 	void Free();
 
 	private:

src/engine/renderer/tr_init.cpp

@@ -1118,6 +1118,12 @@ ScreenshotCmd screenshotPNGRegistration("screenshotPNG", ssFormat_t::SSF_PNG, "p
 					stage->deformIndex = deformIndex;
 				}
 			}
+
+			if ( glConfig2.usingMaterialSystem ) {
+				/* GLSL shaders linked to materials will be invalidated by glsl_restart,
+				so we need to reset them here */
+				materialSystem.GLSLRestart();
+			}
 		}
 	};
 	static GlslRestartCmd glslRestartCmdRegistration;