Replace the render with PBR

In this commit, another PBR render, come from website: https://learnopengl.com/PBR, also included as shaders/pbr-joey.frag

resources.qrc

@@ -10,8 +10,8 @@
     <file>shaders/default.frag</file>
     <file>shaders/default.core.vert</file>
     <file>shaders/default.core.frag</file>
-    <file>shaders/pbr.vert</file>
-    <file>shaders/pbr.frag</file>
+    <file>shaders/pbr-qt.frag</file>
+    <file>shaders/pbr-joey.frag</file>
     <file>ACKNOWLEDGEMENTS.html</file>
     <file>AUTHORS</file>
     <file>CONTRIBUTORS</file>

shaders/default.vert

@@ -10,15 +10,18 @@ varying vec3 vertColor;
 varying vec2 vertTexCoord;
 varying float vertMetalness;
 varying float vertRoughness;
-varying vec3 vertView;
-uniform mat4 projMatrix;
-uniform mat4 mvMatrix;
-uniform mat3 normalMatrix;
-void main() 
+varying vec3 cameraPos;
+uniform mat4 projectionMatrix;
+uniform mat4 modelMatrix;
+uniform mat4 viewMatrix;
+void main()
 {
-    vert = vertex.xyz;
-    vertNormal = normalMatrix * normal;
+    vert = (modelMatrix * vertex).xyz;
+    vertNormal = normalize((modelMatrix * vec4(normal, 1.0)).xyz);
     vertColor = color;
     vertTexCoord = texCoord;
-    gl_Position = projMatrix * mvMatrix * vertex;
+    vertMetalness = metalness;
+    vertRoughness = roughness;
+    cameraPos = vec3(0, 0, -2.1);
+    gl_Position = projectionMatrix * viewMatrix * vec4(vert, 1.0);
 }

shaders/pbr-joey.frag

@@ -0,0 +1,154 @@
+// Copy and modified from Joey's code
+// https://github.com/JoeyDeVries/LearnOpenGL/blob/master/src/6.pbr/1.1.lighting/1.1.pbr.fs
+
+const float PI = 3.14159265359;
+
+// ----------------------------------------------------------------------------
+float DistributionGGX(vec3 N, vec3 H, float roughness)
+{
+    float a = roughness*roughness;
+    float a2 = a*a;
+    float NdotH = max(dot(N, H), 0.0);
+    float NdotH2 = NdotH*NdotH;
+
+    float nom   = a2;
+    float denom = (NdotH2 * (a2 - 1.0) + 1.0);
+    denom = PI * denom * denom;
+
+    return nom / max(denom, 0.001); // prevent divide by zero for roughness=0.0 and NdotH=1.0
+}
+// ----------------------------------------------------------------------------
+float GeometrySchlickGGX(float NdotV, float roughness)
+{
+    float r = (roughness + 1.0);
+    float k = (r*r) / 8.0;
+
+    float nom   = NdotV;
+    float denom = NdotV * (1.0 - k) + k;
+
+    return nom / denom;
+}
+// ----------------------------------------------------------------------------
+float GeometrySmith(vec3 N, vec3 V, vec3 L, float roughness)
+{
+    float NdotV = max(dot(N, V), 0.0);
+    float NdotL = max(dot(N, L), 0.0);
+    float ggx2 = GeometrySchlickGGX(NdotV, roughness);
+    float ggx1 = GeometrySchlickGGX(NdotL, roughness);
+
+    return ggx1 * ggx2;
+}
+// ----------------------------------------------------------------------------
+vec3 fresnelSchlick(float cosTheta, vec3 F0)
+{
+    return F0 + (1.0 - F0) * pow(1.0 - cosTheta, 5.0);
+}
+
+varying highp vec3 vert;
+varying highp vec3 vertNormal;
+varying highp vec3 vertColor;
+varying highp vec2 vertTexCoord;
+varying highp float vertMetalness;
+varying highp float vertRoughness;
+varying highp vec3 cameraPos;
+uniform highp vec3 lightPos;
+uniform highp sampler2D textureId;
+uniform highp int textureEnabled;
+
+const int MAX_LIGHTS = 8;
+struct Light {
+    vec3 position;
+    vec3 color;
+    float intensity;
+};
+int lightCount;
+Light lights[MAX_LIGHTS];
+
+void main() 
+{
+    const highp float vertAmbientOcclusion = 1.0;
+
+    vec3 albedo = vertColor;
+    if (textureEnabled == 1) {
+        albedo = texture2D(textureId, vertTexCoord).rgb;
+    }
+    albedo = pow(albedo, vec3(2.2));
+
+    lightCount = 3;
+    float roughness = vertRoughness;
+    float metalness = vertMetalness;
+
+    // Key light 
+    lights[0].position = vec3(5.0, 5.0, 5.0);
+    lights[0].color = vec3(150.0, 150.0, 150.0);
+    lights[0].intensity = 0.8;
+
+    // Fill light
+    lights[1].position = vec3(-5.0, 5.0, 5.0);
+    lights[1].color = vec3(150.0, 150.0, 150.0);
+    lights[1].intensity = 0.4;
+
+    // Rim light
+    lights[2].position = vec3(0.0, -2.5, -5.0);
+    lights[2].color = vec3(150.0, 150.0, 150.0);
+    lights[2].intensity = 0.2;
+
+    vec3 N = normalize(vertNormal);
+    vec3 V = normalize(cameraPos - vert);
+
+    // calculate reflectance at normal incidence; if dia-electric (like plastic) use F0 
+    // of 0.04 and if it's a metal, use the albedo color as F0 (metallic workflow)    
+    vec3 F0 = vec3(0.04); 
+    F0 = mix(F0, albedo, metalness);
+
+    // reflectance equation
+    vec3 Lo = vec3(0.0);
+    for (int i = 0; i < lightCount; ++i) 
+    {
+        // calculate per-light radiance
+        vec3 L = normalize(lights[i].position - vert);
+        vec3 H = normalize(V + L);
+        float distance = length(lights[i].position - vert);
+        float attenuation = 1.0 / (distance * distance);
+        vec3 radiance = lights[i].color * attenuation;
+
+        // Cook-Torrance BRDF
+        float NDF = DistributionGGX(N, H, roughness);   
+        float G   = GeometrySmith(N, V, L, roughness);      
+        vec3 F    = fresnelSchlick(clamp(dot(H, V), 0.0, 1.0), F0);
+           
+        vec3 nominator    = NDF * G * F; 
+        float denominator = 4.0 * max(dot(N, V), 0.0) * max(dot(N, L), 0.0);
+        vec3 specular = nominator / max(denominator, 0.001); // prevent divide by zero for NdotV=0.0 or NdotL=0.0
+        
+        // kS is equal to Fresnel
+        vec3 kS = F;
+        // for energy conservation, the diffuse and specular light can't
+        // be above 1.0 (unless the surface emits light); to preserve this
+        // relationship the diffuse component (kD) should equal 1.0 - kS.
+        vec3 kD = vec3(1.0) - kS;
+        // multiply kD by the inverse metalness such that only non-metals 
+        // have diffuse lighting, or a linear blend if partly metal (pure metals
+        // have no diffuse light).
+        kD *= 1.0 - metalness;	  
+
+        // scale light by NdotL
+        float NdotL = max(dot(N, L), 0.0);        
+
+        // add to outgoing radiance Lo
+        Lo += lights[i].intensity * (kD * albedo / PI + specular) * radiance * NdotL;  // note that we already multiplied the BRDF by the Fresnel (kS) so we won't multiply by kS again
+    }
+
+    // ambient lighting (note that the next IBL tutorial will replace 
+    // this ambient lighting with environment lighting).
+    vec3 ambient = vec3(0.03) * albedo * vertAmbientOcclusion;
+
+    vec3 color = ambient + Lo;
+
+    // HDR tonemapping
+    color = color / (color + vec3(1.0));
+    // gamma correct
+    color = pow(color, vec3(1.0/2.2)); 
+
+    gl_FragColor = vec4(color, 1.0);
+}

shaders/pbr-qt.frag

@@ -62,7 +62,7 @@ varying highp vec3 vertColor;
 varying highp vec2 vertTexCoord;
 varying highp float vertMetalness;
 varying highp float vertRoughness;
-varying highp vec3 vertView;
+varying highp vec3 cameraPos;
 uniform highp vec3 lightPos;
 uniform highp sampler2D textureId;
 uniform highp int textureEnabled;
@@ -272,11 +272,6 @@ vec4 metalRoughFunction(const in vec4 baseColor,
 
 void main() 
 {
-    highp vec3 color = vertColor;
-    if (textureEnabled == 1) {
-        color = texture2D(textureId, vertTexCoord).rgb;
-    }
-
     // FIXME: don't hard code here
     exposure = 0.0;
     gamma = 2.2;
@@ -286,35 +281,46 @@ void main()
     // https://doc-snapshots.qt.io/qt5-5.12/qt3d-pbr-materials-lights-qml.html
     lightCount = 3;
 
+    // Key light 
     lights[0].type = TYPE_POINT;
-    lights[0].position = vec3(0.0, 5.0, 0.0);
-    lights[0].color = vec3(1.0, 1.0, 1.0);
+    lights[0].position = vec3(5.0, 5.0, 5.0);
+    lights[0].color = vec3(0.588, 0.588, 0.588);
     lights[0].intensity = 5.0;
-    lights[0].constantAttenuation = 1.0;
+    lights[0].constantAttenuation = 0.0;
     lights[0].linearAttenuation = 0.0;
-    lights[0].quadraticAttenuation = 0.0025;
+    lights[0].quadraticAttenuation = 0.0;
 
+    // Fill light
     lights[1].type = TYPE_POINT;
-    lights[1].position = vec3(5.0, 0.0, 0.0);
-    lights[1].color = vec3(1.0, 1.0, 1.0);
-    lights[1].intensity = 0.8;
-    lights[1].constantAttenuation = 1.0;
+    lights[1].position = vec3(-5.0, 5.0, 5.0);
+    lights[1].color = vec3(0.588, 0.588, 0.588);
+    lights[1].intensity = 3.0;
+    lights[1].constantAttenuation = 0.0;
     lights[1].linearAttenuation = 0.0;
-    lights[1].quadraticAttenuation = 0.0025;
+    lights[1].quadraticAttenuation = 0.0;
 
+    // Rim light
     lights[2].type = TYPE_POINT;
-    lights[2].position = vec3(0.0, -5.0, 0.0);
-    lights[2].color = vec3(1.0, 1.0, 1.0);
-    lights[2].intensity = 0.15;
-    lights[2].constantAttenuation = 1.0;
+    lights[2].position = vec3(0.0, -5.0, -5.0);
+    lights[2].color = vec3(0.588, 0.588, 0.588);
+    lights[2].intensity = 2.5;
+    lights[2].constantAttenuation = 0.0;
     lights[2].linearAttenuation = 0.0;
-    lights[2].quadraticAttenuation = 0.0025;
+    lights[2].quadraticAttenuation = 0.0;
+
+    highp vec3 color = vertColor;
+    if (textureEnabled == 1) {
+        color = texture2D(textureId, vertTexCoord).rgb;
+    }
+    color = pow(color, vec3(gamma));
+
+    float roughness = min(0.99, vertRoughness);
 
     gl_FragColor = metalRoughFunction(vec4(color, 1.0),
                                       vertMetalness,
-                                      vertRoughness,
+                                      roughness,
                                       vertAmbientOcclusion,
                                       vert,
-                                      vertView,
+                                      normalize(cameraPos - vert),
                                       vertNormal);
 }

shaders/pbr.vert

@@ -1,27 +0,0 @@
-attribute vec4 vertex;
-attribute vec3 normal;
-attribute vec3 color;
-attribute vec2 texCoord;
-attribute float metalness;
-attribute float roughness;
-varying vec3 vert;
-varying vec3 vertNormal;
-varying vec3 vertColor;
-varying vec2 vertTexCoord;
-varying float vertMetalness;
-varying float vertRoughness;
-varying vec3 vertView;
-uniform mat4 projMatrix;
-uniform mat4 mvMatrix;
-uniform mat3 normalMatrix;
-void main() 
-{
-    vert = vertex.xyz;
-    vertNormal = normalize((projMatrix * mvMatrix * vec4(normal, 1.0)).xyz);
-    vertColor = color;
-    vertTexCoord = texCoord;
-    vertMetalness = metalness;
-    vertRoughness = roughness;
-    vertView = (projMatrix * mvMatrix * vec4(0, 0, 0, 1.0)).xyz;
-    gl_Position = projMatrix * mvMatrix * vertex;
-}

src/modelshaderprogram.cpp

@@ -23,11 +23,10 @@ ModelShaderProgram::ModelShaderProgram(bool usePBR)
         this->addShaderFromSourceCode(QOpenGLShader::Vertex, loadShaderSource(":/shaders/default.core.vert"));
         this->addShaderFromSourceCode(QOpenGLShader::Fragment, loadShaderSource(":/shaders/default.core.frag"));
     } else {
+        this->addShaderFromSourceCode(QOpenGLShader::Vertex, loadShaderSource(":/shaders/default.vert"));
         if (usePBR) {
-            this->addShaderFromSourceCode(QOpenGLShader::Vertex, loadShaderSource(":/shaders/pbr.vert"));
-            this->addShaderFromSourceCode(QOpenGLShader::Fragment, loadShaderSource(":/shaders/pbr.frag"));
+            this->addShaderFromSourceCode(QOpenGLShader::Fragment, loadShaderSource(":/shaders/pbr-qt.frag"));
         } else {
-            this->addShaderFromSourceCode(QOpenGLShader::Vertex, loadShaderSource(":/shaders/default.vert"));
             this->addShaderFromSourceCode(QOpenGLShader::Fragment, loadShaderSource(":/shaders/default.frag"));
         }
     }
@@ -40,27 +39,27 @@ ModelShaderProgram::ModelShaderProgram(bool usePBR)
     this->link();
 
     this->bind();
-    m_projMatrixLoc = this->uniformLocation("projMatrix");
-    m_mvMatrixLoc = this->uniformLocation("mvMatrix");
-    m_normalMatrixLoc = this->uniformLocation("normalMatrix");
+    m_projectionMatrixLoc = this->uniformLocation("projectionMatrix");
+    m_modelMatrixLoc = this->uniformLocation("modelMatrix");
+    m_viewMatrixLoc = this->uniformLocation("viewMatrix");
     m_lightPosLoc = this->uniformLocation("lightPos");
     m_textureIdLoc = this->uniformLocation("textureId");
     m_textureEnabledLoc = this->uniformLocation("textureEnabled");
 }
 
-int ModelShaderProgram::projMatrixLoc()
+int ModelShaderProgram::projectionMatrixLoc()
 {
-    return m_projMatrixLoc;
+    return m_projectionMatrixLoc;
 }
 
-int ModelShaderProgram::mvMatrixLoc()
+int ModelShaderProgram::modelMatrixLoc()
 {
-    return m_mvMatrixLoc;
+    return m_modelMatrixLoc;
 }
 
-int ModelShaderProgram::normalMatrixLoc()
+int ModelShaderProgram::viewMatrixLoc()
 {
-    return m_normalMatrixLoc;
+    return m_viewMatrixLoc;
 }
 
 int ModelShaderProgram::lightPosLoc()

src/modelshaderprogram.h

@@ -6,18 +6,18 @@
 class ModelShaderProgram : public QOpenGLShaderProgram
 {
 public:
-    ModelShaderProgram(bool usePBR=false);
-    int projMatrixLoc();
-    int mvMatrixLoc();
-    int normalMatrixLoc();
+    ModelShaderProgram(bool usePBR=true);
+    int projectionMatrixLoc();
+    int modelMatrixLoc();
+    int viewMatrixLoc();
     int lightPosLoc();
     int textureIdLoc();
     int textureEnabledLoc();
     static const QString &loadShaderSource(const QString &name);
 private:
-    int m_projMatrixLoc;
-    int m_mvMatrixLoc;
-    int m_normalMatrixLoc;
+    int m_projectionMatrixLoc;
+    int m_modelMatrixLoc;
+    int m_viewMatrixLoc;
     int m_lightPosLoc;
     int m_textureIdLoc;
     int m_textureEnabledLoc;

src/modelwidget.cpp

@@ -156,12 +156,10 @@ void ModelWidget::paintGL()
     m_world.rotate(m_yRot / 16.0f, 0, 1, 0);
     m_world.rotate(m_zRot / 16.0f, 0, 0, 1);
 
-    
     m_program->bind();
-    m_program->setUniformValue(m_program->projMatrixLoc(), m_proj);
-    m_program->setUniformValue(m_program->mvMatrixLoc(), m_camera * m_world);
-    QMatrix3x3 normalMatrix = m_world.normalMatrix();
-    m_program->setUniformValue(m_program->normalMatrixLoc(), normalMatrix);
+    m_program->setUniformValue(m_program->projectionMatrixLoc(), m_projection);
+    m_program->setUniformValue(m_program->modelMatrixLoc(), m_world);
+    m_program->setUniformValue(m_program->viewMatrixLoc(), m_camera);
     m_program->setUniformValue(m_program->textureEnabledLoc(), 0);
     
     m_meshBinder.paint(m_program);
@@ -171,8 +169,8 @@ void ModelWidget::paintGL()
 
 void ModelWidget::resizeGL(int w, int h)
 {
-    m_proj.setToIdentity();
-    m_proj.perspective(45.0f, GLfloat(w) / h, 0.01f, 100.0f);
+    m_projection.setToIdentity();
+    m_projection.perspective(45.0f, GLfloat(w) / h, 0.01f, 100.0f);
 }
 
 void ModelWidget::toggleWireframe()

src/modelwidget.h

@@ -70,7 +70,7 @@ private:
 private:
     QPoint m_lastPos;
     ModelMeshBinder m_meshBinder;
-    QMatrix4x4 m_proj;
+    QMatrix4x4 m_projection;
     QMatrix4x4 m_camera;
     QMatrix4x4 m_world;
     static bool m_transparent;