[material] alpha mask will now be packed into the albedo alpha using …

…a min operator
PanosK92 · Nov 13, 2024 · e245d8a · e245d8a
1 parent 8595421
commit e245d8a
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Showing 4 changed files with 31 additions and 50 deletions.
diff --git a/data/shaders/depth_light.hlsl b/data/shaders/depth_light.hlsl
@@ -45,18 +45,11 @@ gbuffer_vertex main_vs(Vertex_PosUvNorTan input, uint instance_id : SV_InstanceI
 
 float4 main_ps(gbuffer_vertex vertex) : SV_Target0
 {
-    // alpha test
-    const float3 f3_value     = pass_get_f3_value();
-    const bool has_alpha_mask = f3_value.x == 1.0f;
-    const bool has_albedo     = f3_value.y == 1.0f;
-
+    const bool has_albedo = pass_get_f3_value().x == 1.0f;
     float alpha_threshold = get_alpha_threshold(vertex.position); // distance based alpha threshold
-    bool mask_alpha       = has_alpha_mask && GET_TEXTURE(material_texture_index_mask).Sample(samplers[sampler_point_wrap], vertex.uv).r <= alpha_threshold;
-    bool mask_albedo      = has_albedo && GET_TEXTURE(material_texture_index_albedo).Sample(samplers[sampler_anisotropic_wrap], vertex.uv).a <= alpha_threshold;
 
-    if (mask_alpha || mask_albedo)
+    if (has_albedo && GET_TEXTURE(material_texture_index_albedo).Sample(samplers[sampler_anisotropic_wrap], vertex.uv).a <= alpha_threshold)
         discard;
 
-    // colored transparent shadows
-    return GetMaterial().color;
+    return GetMaterial().color; // colored transparent shadows
 }
diff --git a/data/shaders/depth_prepass.hlsl b/data/shaders/depth_prepass.hlsl
@@ -39,15 +39,9 @@ gbuffer_vertex main_vs(Vertex_PosUvNorTan input, uint instance_id : SV_InstanceI
 
 void main_ps(gbuffer_vertex vertex)
 {
-    const float3 f3_value     = pass_get_f3_value();
-    const bool has_alpha_mask = f3_value.x == 1.0f;
-    const bool has_albedo     = f3_value.y == 1.0f;
-    const float alpha         = f3_value.z;
+    const bool has_albedo       = pass_get_f3_value().x == 1.0f;
+    const float alpha_threshold = get_alpha_threshold(vertex.position); // distance based alpha threshold
 
-    float alpha_threshold = get_alpha_threshold(vertex.position); // distance based alpha threshold
-    bool mask_alpha       = has_alpha_mask && GET_TEXTURE(material_texture_index_mask).Sample(samplers[sampler_point_wrap], vertex.uv).r <= alpha_threshold;
-    bool mask_albedo      = alpha == 1.0f && has_albedo && GET_TEXTURE(material_texture_index_albedo).Sample(samplers[sampler_anisotropic_wrap], vertex.uv).a <= alpha_threshold;
-
-    if (mask_alpha || mask_albedo)
+    if (has_albedo && GET_TEXTURE(material_texture_index_albedo).Sample(samplers[sampler_anisotropic_wrap], vertex.uv).a <= alpha_threshold)
         discard;
 }
diff --git a/runtime/Rendering/Material.cpp b/runtime/Rendering/Material.cpp
@@ -136,23 +136,14 @@ namespace Spartan
         void merge_alpha_mask_into_color_alpha(vector<byte>& albedo, vector<byte>& mask)
         {
             SP_ASSERT_MSG(albedo.size() == mask.size(), "The dimensions must be equal");
-
-            const float alpha_threshold = 0.6f;
-
+
             for (size_t i = 0; i < albedo.size(); i += 4)
             {
-                float alpha_albedo = static_cast<float>(albedo[i + 3]) / 255.0f;
-                float alpha_mask   = static_cast<float>(mask[i]) / 255.0f;
-
-                // apply the alpha threshold
-                if (alpha_mask >= alpha_threshold)
-                {
-                    albedo[i + 3] = static_cast<byte>(min(alpha_albedo, alpha_mask) * 255.0f);
-                }
-                else
-                {
-                    albedo[i + 3] = static_cast<byte>(alpha_albedo * 255.0f);
-                }
+                float alpha_albedo   = static_cast<float>(albedo[i + 3]) / 255.0f; // channel a
+                float alpha_mask     = static_cast<float>(mask[i]) / 255.0f;       // channel r
+                float alpha_combined = min(alpha_albedo, alpha_mask);
+
+                albedo[i + 3] = static_cast<byte>(alpha_combined * 255.0f);
             }
         }
     }
@@ -357,17 +348,27 @@ namespace Spartan
 
     void Material::PrepareForGPU()
     {
-        RHI_Texture* texture_color      = GetTexture(MaterialTextureType::Color);
-        RHI_Texture* texture_alpha_mask = GetTexture(MaterialTextureType::Color);
-        if (texture_color && texture_alpha_mask)
+        // texture packing
         {
+            // pack alpha mask into albedo alpha
             // note: this can be tested by loading the subway default world
-            // todo: what if a mask is present but an albedo is not?
+            RHI_Texture* texture_color      = GetTexture(MaterialTextureType::Color);
+            RHI_Texture* texture_alpha_mask = GetTexture(MaterialTextureType::AlphaMask);
+            if (texture_alpha_mask)
+            {
+                if (texture_color)
+                { 
+                    if (!texture_color->IsCompressedFormat(texture_color->GetFormat()) && !texture_alpha_mask->IsCompressedFormat(texture_alpha_mask->GetFormat()))
+                    { 
+                        texture_packing::merge_alpha_mask_into_color_alpha(texture_color->GetMip(0, 0).bytes, texture_alpha_mask->GetMip(0, 0).bytes);
+                    }
+                }
+                else
+                {
+                    SetTexture(MaterialTextureType::Color, texture_alpha_mask);
+                }
 
-            if (!texture_color->IsCompressedFormat(texture_color->GetFormat()) && !texture_alpha_mask->IsCompressedFormat(texture_alpha_mask->GetFormat()))
-            { 
-                //texture_packing::merge_alpha_mask_into_color_alpha(texture_color->GetMip(0, 0).bytes, texture_alpha_mask->GetMip(0, 0).bytes);
-                //SetTexture(MaterialTextureType::AlphaMask, nullptr);
+                SetTexture(MaterialTextureType::AlphaMask, nullptr);
             }
         }
 

diff --git a/runtime/Rendering/Renderer_Passes.cpp b/runtime/Rendering/Renderer_Passes.cpp
@@ -588,7 +588,6 @@ namespace Spartan
                         if (Material* material = renderable->GetMaterial())
                         {
                             m_pcb_pass_cpu.set_f3_value(material->HasTextureOfType(MaterialTextureType::Color) ? 1.0f : 0.0f);
-
                             m_pcb_pass_cpu.set_is_transparent_and_material_index(is_transparent_pass, material->GetIndex());
                         }
 
@@ -703,13 +702,7 @@ namespace Spartan
                 {
                     if (Material* material = renderable->GetMaterial())
                     {
-                        // for alpha testing
-                        m_pcb_pass_cpu.set_f3_value(
-                            material->HasTextureOfType(MaterialTextureType::AlphaMask) ? 1.0f : 0.0f,
-                            material->HasTextureOfType(MaterialTextureType::Color) ? 1.0f : 0.0f,
-                            material->GetProperty(MaterialProperty::ColorA)
-                        );
-
+                        m_pcb_pass_cpu.set_f3_value(material->HasTextureOfType(MaterialTextureType::Color) ? 1.0f : 0.0f); // alpha testing
                         m_pcb_pass_cpu.set_is_transparent_and_material_index(is_transparent_pass, material->GetIndex());
                     }