RenderShaderPasses and FillDepthBuffer performance improvement

[Metzelmaennchen]

Currenty the RenderShaderPasses and FillDepthBuffer function are enabling vertex array attrib 1 and 5 for every drawn surface. Due to the fact that each of these surfaces need at least attrib 1 and 5 it makes sense to enable them once, draw all the surfs and disabling them afterwards. Please have a look at following patch, it will drop a lot of redundant state changes and gain some performance:

diff --git a/neo/renderer/draw_common.cpp b/neo/renderer/draw_common.cpp index 40aba8c..33b25ca 100644 --- a/neo/renderer/draw_common.cpp +++ b/neo/renderer/draw_common.cpp @@ -409,9 +409,7 @@ void RB_T_FillDepthBuffer(const drawSurf_t *surf) }

    idDrawVert *ac = (idDrawVert *)vertexCache.Position(tri->ambientCache);

• GL_EnableVertexAttribArray(offsetof(shaderProgram_t, attr_Vertex)); GL_VertexAttribPointer(offsetof(shaderProgram_t, attr_Vertex), 3, GL_FLOAT, false, sizeof(idDrawVert), ac->xyz.ToFloatPtr());

• GL_EnableVertexAttribArray(offsetof(shaderProgram_t, attr_TexCoord));
  GL_VertexAttribPointer(offsetof(shaderProgram_t, attr_TexCoord), 2, GL_FLOAT, false, sizeof(idDrawVert), reinterpret_cast<void 
  
  bool drawSolid = false;

  @@ -492,9 +490,6 @@ void RB_T_FillDepthBuffer(const drawSurf_t *surf) if (shader->GetSort() == SS_SUBVIEW) { GL_State(GLS_DEPTHFUNC_LESS);

  }

• GL_DisableVertexAttribArray(offsetof(shaderProgram_t, attr_Vertex));

• GL_DisableVertexAttribArray(offsetof(shaderProgram_t, attr_TexCoord));

  }

  /* @@ -530,7 +525,8 @@ void RB_STD_FillDepthBuffer(drawSurf_t **drawSurfs, int numDrawSurfs)

  // the first texture will be used for alpha tested surfaces
  GL_SelectTexture(0);

• GL_EnableVertexAttribArray(offsetof(shaderProgram_t, attr_TexCoord));
• GL_EnableVertexAttribArray(offsetof(shaderProgram_t, attr_Vertex));

•  GL_EnableVertexAttribArray(offsetof(shaderProgram_t, attr_TexCoord));
  
  // decal surfaces may enable polygon offset
  glPolygonOffset(r_offsetFactor.GetFloat(), r_offsetUnits.GetFloat());

  @@ -555,6 +551,7 @@ void RB_STD_FillDepthBuffer(drawSurf_t **drawSurfs, int numDrawSurfs)

  endif

  GL_DisableVertexAttribArray(offsetof(shaderProgram_t, attr_TexCoord));

•  GL_DisableVertexAttribArray(offsetof(shaderProgram_t, attr_Vertex));
  
  GL_UseProgram(NULL);

  } @@ -738,8 +735,6 @@ void RB_STD_T_RenderShaderPasses(const drawSurf_t *surf) }

  idDrawVert *ac = (idDrawVert *)vertexCache.Position(tri->ambientCache);

• GL_EnableVertexAttribArray(offsetof(shaderProgram_t, attr_Vertex));
• GL_EnableVertexAttribArray(offsetof(shaderProgram_t, attr_TexCoord)); GL_VertexAttribPointer(offsetof(shaderProgram_t, attr_Vertex), 3, GL_FLOAT, false, sizeof(idDrawVert), ac->xyz.ToFloatPtr()); GL_VertexAttribPointer(offsetof(shaderProgram_t, attr_TexCoord), 2, GL_FLOAT, false, sizeof(idDrawVert), reinterpret_cast<void

@@ -916,9 +911,6 @@ void RB_STD_T_RenderShaderPasses(const drawSurf_t *surf) } }

• GL_DisableVertexAttribArray(offsetof(shaderProgram_t, attr_Vertex));

  - GL_DisableVertexAttribArray(offsetof(shaderProgram_t, attr_TexCoord));

    // reset polygon offset
    if (shader->TestMaterialFlag(MF_POLYGONOFFSET)) {
            glDisable(GL_POLYGON_OFFSET_FILL);

@@ -970,6 +962,7 @@ int RB_STD_DrawShaderPasses(drawSurf_t **drawSurfs, int numDrawSurfs) globalImages->BindNull();

    GL_SelectTexture(0);

•  GL_EnableVertexAttribArray(offsetof(shaderProgram_t, attr_Vertex));
  GL_EnableVertexAttribArray(offsetof(shaderProgram_t, attr_TexCoord));
  
  RB_SetProgramEnvironment();

  @@ -1005,6 +998,7 @@ int RB_STD_DrawShaderPasses(drawSurf_t **drawSurfs, int numDrawSurfs)

  endif

  GL_DisableVertexAttribArray(offsetof(shaderProgram_t, attr_TexCoord));

•  GL_DisableVertexAttribArray(offsetof(shaderProgram_t, attr_Vertex));
  
  GL_UseProgram(NULL);