GL3: Use one projection-view matrix in shaders

instead of separate projection and view matrices - this way there is
one less mat4 multiplication in the 3D vertex shaders.

src/client/refresh/gl3/gl3_main.c

@@ -1316,6 +1316,7 @@ GL3_MYgluPerspective(GLdouble fovy, GLdouble aspect, GLdouble zNear, GLdouble zF
 
 	// the following emulates glFrustum(left, right, bottom, top, zNear, zFar)
 	// see https://www.khronos.org/registry/OpenGL-Refpages/gl2.1/xhtml/glFrustum.xml
+	//  or http://docs.gl/gl2/glFrustum#description (looks better in non-Firefox browsers)
 	A = (right+left)/(right-left);
 	B = (top+bottom)/(top-bottom);
 	C = -(zFar+zNear)/(zFar-zNear);
@@ -1431,7 +1432,7 @@ SetupGL(void)
 	{
 		float screenaspect = (float)gl3_newrefdef.width / gl3_newrefdef.height;
 		float dist = (r_farsee->value == 0) ? 4096.0f : 8192.0f;
-		gl3state.uni3DData.transProjMat4 = GL3_MYgluPerspective(gl3_newrefdef.fov_y, screenaspect, 4, dist);
+		gl3state.projMat3D = GL3_MYgluPerspective(gl3_newrefdef.fov_y, screenaspect, 4, dist);
 	}
 
 	glCullFace(GL_FRONT);
@@ -1440,7 +1441,7 @@ SetupGL(void)
 	{
 		// first put Z axis going up
 		hmm_mat4 viewMat = {{
-			{  0, 0, -1, 0 }, // first *column* (the matrix is colum-major)
+			{  0, 0, -1, 0 }, // first *column* (the matrix is column-major)
 			{ -1, 0,  0, 0 },
 			{  0, 1,  0, 0 },
 			{  0, 0,  0, 1 }
@@ -1455,9 +1456,13 @@ SetupGL(void)
 		hmm_vec3 trans = HMM_Vec3(-gl3_newrefdef.vieworg[0], -gl3_newrefdef.vieworg[1], -gl3_newrefdef.vieworg[2]);
 		viewMat = HMM_MultiplyMat4( viewMat, HMM_Translate(trans) );
 
-		gl3state.uni3DData.transViewMat4 = viewMat;
+		gl3state.viewMat3D = viewMat;
 	}
 
+	// just use one projection-view-matrix (premultiplied here)
+	// so we have one less mat4 multiplication in the 3D shaders
+	gl3state.uni3DData.transProjViewMat4 = HMM_MultiplyMat4(gl3state.projMat3D, gl3state.viewMat3D);
+
 	gl3state.uni3DData.transModelMat4 = gl3_identityMat4;
 
 	gl3state.uni3DData.time = gl3_newrefdef.time;

src/client/refresh/gl3/gl3_mesh.c

@@ -650,7 +650,7 @@ GL3_DrawAliasModel(entity_t *entity)
 	vec3_t shadelight;
 	vec3_t shadevector;
 	gl3image_t *skin;
-	hmm_mat4 origProjMat = {0}; // use for left-handed rendering
+	hmm_mat4 origProjViewMat = {0}; // use for left-handed rendering
 	// used to restore ModelView matrix after changing it for this entities position/rotation
 	hmm_mat4 origModelMat = {0};
 
@@ -817,19 +817,20 @@ GL3_DrawAliasModel(entity_t *entity)
 	{
 		extern hmm_mat4 GL3_MYgluPerspective(GLdouble fovy, GLdouble aspect, GLdouble zNear, GLdouble zFar);
 
-		origProjMat = gl3state.uni3DData.transProjMat4;
+		origProjViewMat = gl3state.uni3DData.transProjViewMat4;
 
 		// render weapon with a different FOV (r_gunfov) so it's not distorted at high view FOV
 		float screenaspect = (float)gl3_newrefdef.width / gl3_newrefdef.height;
 		float dist = (r_farsee->value == 0) ? 4096.0f : 8192.0f;
 
+		hmm_mat4 projMat;
 		if (r_gunfov->value < 0)
 		{
-			gl3state.uni3DData.transProjMat4 = GL3_MYgluPerspective(gl3_newrefdef.fov_y, screenaspect, 4, dist);
+			projMat = GL3_MYgluPerspective(gl3_newrefdef.fov_y, screenaspect, 4, dist);
 		}
 		else
 		{
-			gl3state.uni3DData.transProjMat4 = GL3_MYgluPerspective(r_gunfov->value, screenaspect, 4, dist);
+			projMat = GL3_MYgluPerspective(r_gunfov->value, screenaspect, 4, dist);
 		}
 
 		if(gl_lefthand->value == 1.0F)
@@ -838,12 +839,13 @@ GL3_DrawAliasModel(entity_t *entity)
 			// of projection matrix
 			for(int i=0; i<4; ++i)
 			{
-				gl3state.uni3DData.transProjMat4.Elements[0][i] = -gl3state.uni3DData.transProjMat4.Elements[0][i];
+				projMat.Elements[0][i] = - projMat.Elements[0][i];
 			}
 			//GL3_UpdateUBO3D(); Note: GL3_RotateForEntity() will call this,no need to do it twice before drawing
 
 			glCullFace(GL_BACK);
 		}
+		gl3state.uni3DData.transProjViewMat4 = HMM_MultiplyMat4(projMat, gl3state.viewMat3D);
 	}
 
 
@@ -916,7 +918,7 @@ GL3_DrawAliasModel(entity_t *entity)
 
 	if (entity->flags & RF_WEAPONMODEL)
 	{
-		gl3state.uni3DData.transProjMat4 = origProjMat;
+		gl3state.uni3DData.transProjViewMat4 = origProjViewMat;
 		GL3_UpdateUBO3D();
 		if(gl_lefthand->value == 1.0F)
 			glCullFace(GL_FRONT);

src/client/refresh/gl3/gl3_shaders.c

@@ -359,8 +359,7 @@ static const char* vertexCommon3D = MULTILINE_STRING(
 		// for UBO shared between all 3D shaders
 		layout (std140) uniform uni3D
 		{
-			mat4 transProj;
+			mat4 transProjView;
-			mat4 transView;
 			mat4 transModel;
 
 			float scroll; // for SURF_FLOWING
@@ -388,13 +387,11 @@ static const char* fragmentCommon3D = MULTILINE_STRING(
 			float intensity2D; // for HUD, menus etc
 
 			vec4 color; // really?
-
 		};
 		// for UBO shared between all 3D shaders
 		layout (std140) uniform uni3D
 		{
-			mat4 transProj;
+			mat4 transProjView;
-			mat4 transView;
 			mat4 transModel;
 
 			float scroll; // for SURF_FLOWING
@@ -415,7 +412,7 @@ static const char* vertexSrc3D = MULTILINE_STRING(
 		void main()
 		{
 			passTexCoord = texCoord;
-			gl_Position = transProj * transView * transModel * vec4(position, 1.0);
+			gl_Position = transProjView * transModel * vec4(position, 1.0);
 		}
 );
 
@@ -426,7 +423,7 @@ static const char* vertexSrc3Dflow = MULTILINE_STRING(
 		void main()
 		{
 			passTexCoord = texCoord + vec2(scroll, 0);
-			gl_Position = transProj * transView * transModel * vec4(position, 1.0);
+			gl_Position = transProjView * transModel * vec4(position, 1.0);
 		}
 );
 
@@ -449,7 +446,7 @@ static const char* vertexSrc3Dlm = MULTILINE_STRING(
 			passNormal = normalize(worldNormal.xyz);
 			passLightFlags = lightFlags;
 
-			gl_Position = transProj * transView * worldCoord;
+			gl_Position = transProjView * worldCoord;
 		}
 );
 
@@ -472,7 +469,7 @@ static const char* vertexSrc3DlmFlow = MULTILINE_STRING(
 			passNormal = normalize(worldNormal.xyz);
 			passLightFlags = lightFlags;
 
-			gl_Position = transProj * transView * worldCoord;
+			gl_Position = transProjView * worldCoord;
 		}
 );
 
@@ -771,7 +768,7 @@ static const char* vertexSrc3Dwater = MULTILINE_STRING(
 		{
 			passTexCoord = texCoord;
 
-			gl_Position = transProj * transView * transModel * vec4(position, 1.0);
+			gl_Position = transProjView * transModel * vec4(position, 1.0);
 		}
 );
 
@@ -785,7 +782,7 @@ static const char* vertexSrcAlias = MULTILINE_STRING(
 		{
 			passColor = vertColor*overbrightbits;
 			passTexCoord = texCoord;
-			gl_Position = transProj * transView * transModel * vec4(position, 1.0);
+			gl_Position = transProjView* transModel * vec4(position, 1.0);
 		}
 );
 
@@ -838,7 +835,7 @@ static const char* vertexSrcParticles = MULTILINE_STRING(
 		void main()
 		{
 			passColor = vertColor;
-			gl_Position = transProj * transView * transModel * vec4(position, 1.0);
+			gl_Position = transProjView * transModel * vec4(position, 1.0);
 
 			// abusing texCoord for pointSize, pointDist for particles
 			float pointDist = texCoord.y*0.1; // with factor 0.1 it looks good.
@@ -1167,8 +1164,7 @@ static void initUBOs(void)
 	glBufferData(GL_UNIFORM_BUFFER, sizeof(gl3state.uni2DData), &gl3state.uni2DData, GL_DYNAMIC_DRAW);
 
 	// the matrices will be set to something more useful later, before being used
-	gl3state.uni3DData.transProjMat4 = HMM_Mat4();
+	gl3state.uni3DData.transProjViewMat4 = HMM_Mat4();
-	gl3state.uni3DData.transViewMat4 = HMM_Mat4();
 	gl3state.uni3DData.transModelMat4 = gl3_identityMat4;
 	gl3state.uni3DData.scroll = 0.0f;
 	gl3state.uni3DData.time = 0.0f;

src/client/refresh/gl3/header/local.h

@@ -155,8 +155,7 @@ typedef struct
 
 typedef struct
 {
-	hmm_mat4 transProjMat4;
+	hmm_mat4 transProjViewMat4; // gl3state.projMat3D * gl3state.viewMat3D - so we don't have to do this in the shader
-	hmm_mat4 transViewMat4;
 	hmm_mat4 transModelMat4;
 
 	GLfloat scroll; // for SURF_FLOWING
@@ -269,6 +268,8 @@ typedef struct
 	GLuint uni3DUBO;
 	GLuint uniLightsUBO;
 
+	hmm_mat4 projMat3D;
+	hmm_mat4 viewMat3D;
 } gl3state_t;
 
 extern gl3config_t gl3config;