[Render/Renderer] Added setBlendFunction()

- Initializing the RenderSystem enables the blending capability
  - No blend function is set, as transparency isn't properly used yet

- The cubemap is displayed before all entities
  - Being supposed to be behind everything else, it makes more sense and allows for a proper transparency workflow

- Setting a transparency map, either loaded from an OBJ or set as a default map, sets a nearest filter
  - As a transparency map is supposed to be binary, the texels shouldn't be interpolated

include/RaZ/Render/Renderer.hpp

@@ -151,6 +151,30 @@ enum class FaceOrientation : unsigned int {
   FRONT_BACK = 1032 /* GL_FRONT_AND_BACK */  ///<
 };
 
+enum class BlendFactor : unsigned int {
+  ZERO                     = 0     /* GL_ZERO                     */, ///<
+  ONE                      = 1     /* GL_ONE                      */, ///<
+  SRC_COLOR                = 768   /* GL_SRC_COLOR                */, ///<
+  ONE_MINUS_SRC_COLOR      = 769   /* GL_ONE_MINUS_SRC_COLOR      */, ///<
+  SRC_ALPHA                = 770   /* GL_SRC_ALPHA                */, ///<
+  ONE_MINUS_SRC_ALPHA      = 771   /* GL_ONE_MINUS_SRC_ALPHA      */, ///<
+  DST_ALPHA                = 772   /* GL_DST_ALPHA                */, ///<
+  ONE_MINUS_DST_ALPHA      = 773   /* GL_ONE_MINUS_DST_ALPHA      */, ///<
+  DST_COLOR                = 774   /* GL_DST_COLOR                */, ///<
+  ONE_MINUS_DST_COLOR      = 775   /* GL_ONE_MINUS_DST_COLOR      */, ///<
+  SRC_ALPHA_SATURATE       = 776   /* GL_SRC_ALPHA_SATURATE       */, ///<
+  CONSTANT_COLOR           = 32769 /* GL_CONSTANT_COLOR           */, ///<
+  ONE_MINUS_CONSTANT_COLOR = 32770 /* GL_ONE_MINUS_CONSTANT_COLOR */, ///<
+  CONSTANT_ALPHA           = 32771 /* GL_CONSTANT_ALPHA           */, ///<
+  ONE_MINUS_CONSTANT_ALPHA = 32772 /* GL_ONE_MINUS_CONSTANT_ALPHA */, ///<
+#if !defined(USE_OPENGL_ES)
+  SRC1_COLOR               = 35065 /* GL_SRC1_COLOR               */, ///<
+  ONE_MINUS_SRC1_COLOR     = 35066 /* GL_ONE_MINUS_SRC1_COLOR     */, ///<
+  SRC1_ALPHA               = 34185 /* GL_SRC1_ALPHA               */, ///<
+  ONE_MINUS_SRC1_ALPHA     = 35067 /* GL_ONE_MINUS_SRC1_ALPHA     */  ///<
+#endif
+};
+
 enum class PolygonMode : unsigned int {
   POINT = 6912 /* GL_POINT */, ///<
   LINE  = 6913 /* GL_LINE  */, ///<
@@ -909,6 +933,7 @@ class Renderer {
   /// \param mask Bitmask defining which stencil bits can be written.
   /// \param orientation Face orientation for which to set the mask.
   static void setStencilMask(unsigned int mask, FaceOrientation orientation = FaceOrientation::FRONT_BACK);
+  static void setBlendFunction(BlendFactor source, BlendFactor destination);
   static void setFaceCulling(FaceOrientation orientation);
 #if !defined(USE_OPENGL_ES)
   static void setPolygonMode(FaceOrientation orientation, PolygonMode mode);

src/RaZ/Data/ObjLoad.cpp

@@ -49,7 +49,7 @@ inline void loadMtl(const FilePath& mtlFilePath,
     std::string nextValue;
     file >> tag >> nextValue;
 
-    if (tag[0] == 'K') {                 // Standard properties
+    if (tag[0] == 'K') {                 // Standard properties [K*]
       std::string secondValue;
       std::string thirdValue;
       file >> secondValue >> thirdValue;
@@ -64,7 +64,7 @@ inline void loadMtl(const FilePath& mtlFilePath,
         material.getProgram().setAttribute(values, MaterialAttribute::Ambient);
       else if (tag[1] == 's')            // Specular factor [Ks]
         material.getProgram().setAttribute(values, MaterialAttribute::Specular);
-    } else if (tag[0] == 'P') {          // PBR properties
+    } else if (tag[0] == 'P') {          // PBR properties [P*]
       const float factor = std::stof(nextValue);
 
       if (tag[1] == 'm')                 // Metallic factor [Pm]
@@ -73,13 +73,13 @@ inline void loadMtl(const FilePath& mtlFilePath,
         material.getProgram().setAttribute(factor, MaterialAttribute::Roughness);
 
       materialType = MaterialType::COOK_TORRANCE;
-    } else if (tag[0] == 'm') {          // Import texture
+    } else if (tag[0] == 'm') {          // Import texture [map_*]
       const Texture2DPtr map = loadTexture(mtlFilePath, nextValue);
 
       if (map == nullptr)
         continue;
 
-      if (tag[4] == 'K') {               // Standard maps
+      if (tag[4] == 'K') {               // Standard maps [map_K*]
         if (tag[5] == 'd')               // Diffuse/albedo map [map_Kd]
           material.getProgram().setTexture(map, MaterialTexture::BaseColor);
         else if (tag[5] == 'e')          // Emissive map [map_Ke]
@@ -88,19 +88,20 @@ inline void loadMtl(const FilePath& mtlFilePath,
           material.getProgram().setTexture(map, MaterialTexture::Ambient);
         else if (tag[5] == 's')          // Specular map [map_Ks]
           material.getProgram().setTexture(map, MaterialTexture::Specular);
-      } else if (tag[4] == 'P') {       // PBR maps
+      } else if (tag[4] == 'P') {       // PBR maps [map_P*]
         if (tag[5] == 'm')               // Metallic map [map_Pm]
           material.getProgram().setTexture(map, MaterialTexture::Metallic);
         else if (tag[5] == 'r')          // Roughness map [map_Pr]
           material.getProgram().setTexture(map, MaterialTexture::Roughness);
 
         materialType = MaterialType::COOK_TORRANCE;
       } else if (tag[4] == 'd') {        // Transparency map [map_d]
+        map->setFilter(TextureFilter::NEAREST, TextureFilter::NEAREST, TextureFilter::NEAREST);
         material.getProgram().setTexture(map, MaterialTexture::Transparency);
       } else if (tag[4] == 'b') {        // Bump map [map_bump]
         material.getProgram().setTexture(map, MaterialTexture::Bump);
       }
-    } else if (tag[0] == 'd') {          // Transparency factor
+    } else if (tag[0] == 'd') {          // Transparency factor [d]
       material.getProgram().setAttribute(std::stof(nextValue), MaterialAttribute::Transparency);
     } else if (tag[0] == 'T') {
       if (tag[1] == 'r')                 // Transparency factor (alias, 1 - d) [Tr]

src/RaZ/Render/Material.cpp

@@ -79,8 +79,11 @@ void Material::loadType(MaterialType type) {
         m_program.setTexture(Texture2D::create(ColorPreset::White), MaterialTexture::Ambient);
       if (!m_program.hasTexture(MaterialTexture::Specular))
         m_program.setTexture(Texture2D::create(ColorPreset::White), MaterialTexture::Specular);
-      if (!m_program.hasTexture(MaterialTexture::Transparency))
-        m_program.setTexture(Texture2D::create(ColorPreset::White), MaterialTexture::Transparency);
+      if (!m_program.hasTexture(MaterialTexture::Transparency)) {
+        auto transparencyMap = Texture2D::create(ColorPreset::White);
+        transparencyMap->setFilter(TextureFilter::NEAREST, TextureFilter::NEAREST, TextureFilter::NEAREST);
+        m_program.setTexture(std::move(transparencyMap), MaterialTexture::Transparency);
+      }
       if (!m_program.hasTexture(MaterialTexture::Bump))
         m_program.setTexture(Texture2D::create(ColorPreset::White), MaterialTexture::Bump);
 

src/RaZ/Render/RenderGraph.cpp

@@ -74,6 +74,9 @@ void RenderGraph::execute(RenderSystem& renderSystem) {
   renderSystem.sendInverseProjectionMatrix(camera.getInverseProjectionMatrix());
   renderSystem.sendViewProjectionMatrix(camera.getProjectionMatrix() * camera.getViewMatrix());
 
+  if (renderSystem.hasCubemap())
+    renderSystem.getCubemap().draw();
+
   renderSystem.m_modelUbo.bind();
 
   for (const Entity* entity : renderSystem.m_entities) {
@@ -89,9 +92,6 @@ void RenderGraph::execute(RenderSystem& renderSystem) {
     meshRenderer.draw();
   }
 
-  if (renderSystem.hasCubemap())
-    renderSystem.getCubemap().draw();
-
   geometryFramebuffer.unbind();
 
 #if !defined(USE_OPENGL_ES)

src/RaZ/Render/RenderSystem.cpp

@@ -189,6 +189,7 @@ void RenderSystem::initialize() {
   //  As such, if reaching here, the Renderer is necessarily already functional. Ideally, this call below should be the only one in the whole program
   Renderer::initialize();
   Renderer::enable(Capability::CULL);
+  Renderer::enable(Capability::BLEND);
   Renderer::enable(Capability::DEPTH_TEST);
   Renderer::enable(Capability::STENCIL_TEST);
 #if !defined(USE_OPENGL_ES)

src/RaZ/Render/Renderer.cpp

@@ -304,6 +304,14 @@ void Renderer::setStencilMask(unsigned int mask, FaceOrientation orientation) {
   printConditionalErrors();
 }
 
+void Renderer::setBlendFunction(BlendFactor source, BlendFactor destination) {
+  assert("Error: The Renderer must be initialized before calling its functions." && isInitialized());
+
+  glBlendFunc(static_cast<unsigned int>(source), static_cast<unsigned int>(destination));
+
+  printConditionalErrors();
+}
+
 void Renderer::setFaceCulling(FaceOrientation orientation) {
   assert("Error: The Renderer must be initialized before calling its functions." && isInitialized());
 

src/RaZ/Render/SsrRenderProcess.cpp

@@ -1,5 +1,4 @@
 #include "RaZ/Render/SsrRenderProcess.hpp"
-#include "RaZ/Render/Renderer.hpp"
 #include "RaZ/Render/RenderGraph.hpp"
 #include "RaZ/Render/Texture.hpp"