Use sRGB textures and backbuffer

Author: pezcode

src/Cluster.cpp

@@ -86,7 +86,7 @@ void Cluster::initialize(int _argc, char* _argv[])
     if(config->profile)
         bgfx::setDebug(BGFX_DEBUG_PROFILER);
 
-    uint32_t resetFlags = BGFX_RESET_MAXANISOTROPY;
+    uint32_t resetFlags = BGFX_RESET_MAXANISOTROPY | BGFX_RESET_SRGB_BACKBUFFER;
     if(config->vsync)
         resetFlags |= BGFX_RESET_VSYNC;
     reset(resetFlags);

src/Renderer/Shaders/fs_deferred_pointlight.sc

@@ -52,6 +52,4 @@ void main()
     }
 
     gl_FragColor = vec4(radianceOut, 1.0);
-
-    //gl_FragColor = vec4(0.3, 0.0, 0.0, 1.0);
 }

src/Renderer/Shaders/fs_tonemap.sc

@@ -91,8 +91,5 @@ void main()
         result.rgb = tonemap_aces_luminance(result.rgb);
     }
 
-    // gamma correction
-    result.rgb = LinearTosRGB(result.rgb);
-
     gl_FragColor = result;
 }

src/Renderer/Shaders/pbr.sh

@@ -2,7 +2,6 @@
 #define PBR_SH_HEADER_GUARD
 
 #include "samplers.sh"
-#include "tonemapping.sh"
 
 // only define this if you need to retrieve the material parameters
 // without it you can still use the struct definition or BRDF functions
@@ -55,9 +54,7 @@ vec4 pbrBaseColor(vec2 texcoord)
 {
     if(u_hasBaseColorTexture)
     {
-        vec4 color = texture2D(s_texBaseColor, texcoord);
-        // GLTF base color texture is stored as sRGB
-        return vec4(sRGBToLinear(color.rgb), color.a) * u_baseColorFactor;
+        return texture2D(s_texBaseColor, texcoord) * u_baseColorFactor;
     }
     else
     {
@@ -111,7 +108,7 @@ vec3 pbrEmissive(vec2 texcoord)
 {
     if(u_hasEmissiveTexture)
     {
-        return sRGBToLinear(texture2D(s_texEmissive, texcoord).rgb) * u_emissiveFactor;
+        return texture2D(s_texEmissive, texcoord).rgb * u_emissiveFactor;
     }
     else
     {

src/Renderer/Shaders/tonemapping.sh

@@ -1,35 +1,6 @@
 #ifndef TONEMAPPING_SH_HEADER_GUARD
 #define TONEMAPPING_SH_HEADER_GUARD
 
-// Taken from
-// https://gamedev.stackexchange.com/a/148088/45850
-
-// sRGB gamma encoding
-vec3 LinearTosRGB(vec3 linearRGB)
-{
-#ifdef SRGB_CONVERSION_FAST
-    return pow(linearRGB, vec3_splat(1.0/2.2));
-#else
-    vec3 cutoff = step(linearRGB, vec3_splat(0.0031308));
-    vec3 higher = 1.055 * pow(linearRGB, vec3_splat(1.0/2.4)) - 0.055;
-    vec3 lower = linearRGB * 12.92;
-    return mix(higher, lower, cutoff);
-#endif
-}
-
-// sRGB gamma decoding
-vec3 sRGBToLinear(vec3 sRGB)
-{
-#ifdef SRGB_CONVERSION_FAST
-    return pow(sRGB, vec3_splat(2.2));
-#else
-    vec3 cutoff = step(sRGB, vec3_splat(0.04045));
-    vec3 higher = pow((sRGB + 0.055) / 1.055, vec3_splat(2.4));
-    vec3 lower = sRGB / 12.92;
-    return mix(higher, lower, cutoff);
-#endif
-}
-
 // relative luminance of linear RGB(!)
 // BT.709 primaries
 float luminance(vec3 RGB)

src/Scene/Scene.cpp

@@ -141,6 +141,10 @@ bool Scene::load(const char* file)
                 }
             }
 
+            center = minBounds + (maxBounds - minBounds) / 2.0f;
+            glm::vec3 extent = glm::abs(maxBounds - minBounds);
+            diagonal = glm::sqrt(glm::dot(extent, extent));
+
             char dir[bx::kMaxFilePath] = "";
             bx::strCopy(dir, BX_COUNTOF(dir), bx::FilePath(file).getPath());
             for(unsigned int i = 0; i < scene->mNumMaterials; i++)
@@ -214,9 +218,6 @@ Mesh Scene::loadMesh(const aiMesh* mesh)
 
         minBounds = glm::min(minBounds, { pos.x, pos.y, pos.z });
         maxBounds = glm::max(maxBounds, { pos.x, pos.y, pos.z });
-        center = minBounds + (maxBounds - minBounds) / 2.0f;
-        glm::vec3 extent = glm::abs(maxBounds - minBounds);
-        diagonal = glm::sqrt(glm::dot(extent, extent));
 
         aiVector3D nrm = mesh->mNormals[i];
         vertex.nx = nrm.x;
@@ -286,7 +287,7 @@ Material Scene::loadMaterial(const aiMaterial* material, const char* dir)
         aiString pathBaseColor;
         pathBaseColor.Set(dir);
         pathBaseColor.Append(fileBaseColor.C_Str());
-        out.baseColorTexture = loadTexture(pathBaseColor.C_Str());
+        out.baseColorTexture = loadTexture(pathBaseColor.C_Str(), true /* sRGB */);
     }
 
     aiColor4D baseColorFactor;
@@ -352,7 +353,7 @@ Material Scene::loadMaterial(const aiMaterial* material, const char* dir)
         aiString pathEmissive;
         pathEmissive.Set(dir);
         pathEmissive.Append(fileEmissive.C_Str());
-        out.emissiveTexture = loadTexture(pathEmissive.C_Str());
+        out.emissiveTexture = loadTexture(pathEmissive.C_Str(), true /* sRGB */);
     }
 
 // assimp doesn't define this
@@ -385,7 +386,7 @@ Camera Scene::loadCamera(const aiCamera* camera)
     return cam;
 }
 
-bgfx::TextureHandle Scene::loadTexture(const char* file)
+bgfx::TextureHandle Scene::loadTexture(const char* file, bool sRGB)
 {
     void* data = nullptr;
     uint32_t size = 0;
@@ -417,16 +418,19 @@ bgfx::TextureHandle Scene::loadTexture(const char* file)
             image);
         BX_FREE(&allocator, data);
 
-        if(bgfx::isTextureValid(
-               0, false, image->m_numLayers, (bgfx::TextureFormat::Enum)image->m_format, BGFX_TEXTURE_NONE))
+        uint64_t textureFlags = BGFX_TEXTURE_NONE | BGFX_SAMPLER_MIN_ANISOTROPIC | BGFX_SAMPLER_MAG_ANISOTROPIC;
+        if(sRGB)
+            textureFlags |= BGFX_TEXTURE_SRGB;
+
+        if(bgfx::isTextureValid(0, false, image->m_numLayers, (bgfx::TextureFormat::Enum)image->m_format, textureFlags))
         {
             bgfx::TextureHandle tex =
                 bgfx::createTexture2D((uint16_t)image->m_width,
                                       (uint16_t)image->m_height,
                                       image->m_numMips > 1,
                                       image->m_numLayers,
                                       (bgfx::TextureFormat::Enum)image->m_format,
-                                      BGFX_TEXTURE_NONE | BGFX_SAMPLER_MIN_ANISOTROPIC | BGFX_SAMPLER_MAG_ANISOTROPIC,
+                                      textureFlags,
                                       mem);
             //bgfx::setName(tex, file); // causes debug errors with DirectX SetPrivateProperty duplicate
             return tex;

src/Scene/Scene.h

@@ -47,5 +47,5 @@ class Scene
     static Material loadMaterial(const aiMaterial* material, const char* dir);
     static Camera loadCamera(const aiCamera* camera);
 
-    static bgfx::TextureHandle loadTexture(const char* file);
+    static bgfx::TextureHandle loadTexture(const char* file, bool sRGB = false);
 };

src/UI.cpp

@@ -6,8 +6,10 @@
 #include "Renderer/Renderer.h"
 #include "Log/UISink.h"
 #include "Log/Log.h"
+#include <glm/gtc/type_ptr.hpp>
+#include <glm/gtc/color_space.hpp>
 #include <bx/string.h>
-#include <IconsForkAwesome.h>
+#include <IconsForkAwesome_c.h>
 #include <functional>
 #include <cctype>
 
@@ -29,11 +31,20 @@ void ClusterUI::initialize()
 
     ImGuiIO& io = ImGui::GetIO();
     //io.IniFilename = nullptr;   // don't save window positions etc. to ini
-    io.MouseDrawCursor = true; // let imgui draw cursors
+    //io.MouseDrawCursor = true; // let imgui draw cursors
 
     ImGuiStyle& style = ImGui::GetStyle();
     ImGui::StyleColorsDark(&style);
 
+    // convert imgui style colors to linear RGB
+    // since we have an sRGB backbuffer
+    for(size_t i = 0; i < ImGuiCol_COUNT; i++)
+    {
+        glm::vec3 sRGB = glm::make_vec3(&style.Colors[i].x);
+        glm::vec3 linear = glm::convertSRGBToLinear(sRGB);
+        style.Colors[i] = ImVec4(linear.x, linear.y, linear.z, style.Colors[i].w);
+    }
+
     // no round corners
     style.WindowRounding = 0.0f;
     style.ChildRounding = 0.0f;