start working on a immediate mode drawing API

2 files changed, 162 insertions, 0 deletions

diff --git a/assets/shaders/pbr_textured.frag b/assets/shaders/pbr_textured.frag
new file mode 100644
index 0000000..132c449
--- /dev/null
+++ b/assets/shaders/pbr_textured.frag
@@ -0,0 +1,134 @@
+#version 410 core
+
+out vec4 FragColor;
+
+in vec3 fragWorldPos;
+in vec3 fragNormal;
+in vec2 fragTexCoords;
+
+struct PointLight {
+    vec4 position;
+    vec4 color;
+};
+
+// --- Uniforms
+
+// Lights data
+#define NUM_POINT_LIGHTS 4
+uniform Scene_Lights {
+    PointLight pointLights[NUM_POINT_LIGHTS];
+    vec4 viewPos;
+} scene;
+
+// Material Textures
+uniform sampler2D albedoMap;
+uniform sampler2D metallicRoughnessMap;
+// uniform sampler2D roughnessMap;
+uniform sampler2D aoMap;
+uniform sampler2D normalMap;
+
+const float PI = 3.14;
+
+// Forward declarations
+vec3 fresnelSchlick(float cosTheta, vec3 F0);
+float DistributionGGX(vec3 N, vec3 H, float roughness);
+float GeometrySchlickGGX(float NdotV, float roughness);
+float GeometrySmith(vec3 N, vec3 V, vec3 L, float roughness);
+
+void main() {
+  vec3 albedo     = pow(texture(albedoMap, fragTexCoords).rgb, vec3(2.2));
+  // vec3 normal     = getNormalFromNormalMap();
+  float metallic  = texture(metallicRoughnessMap, fragTexCoords).g;
+  float roughness = texture(metallicRoughnessMap, fragTexCoords).b;
+  float ao        = texture(aoMap, fragTexCoords).r;
+
+  vec3 norm = normalize(fragNormal); // N
+  vec3 N = norm;
+  vec3 viewDir = normalize(vec3(scene.viewPos) - fragWorldPos); // V
+  vec3 V = viewDir;
+
+  vec3 F0 = vec3(0.04);
+  F0      = mix(F0, albedo, metallic);
+
+  vec3 Lo = vec3(0.0);
+  for (int i = 0; i < 4; ++i) {
+    vec3 lightVec = normalize(vec3(scene.pointLights[i].position) - fragWorldPos); // L
+    vec3 L = lightVec;
+    vec3 halfway = normalize(viewDir + lightVec); // H
+    vec3 H = halfway;
+    float distance = length(vec3(scene.pointLights[i].position) - fragWorldPos);
+    float attenuation = 1.0 / (distance * distance);
+    vec3 radiance = vec3(scene.pointLights[i].color) * attenuation;
+
+    // cook-torrance brdf
+    float NDF = DistributionGGX(norm, halfway, roughness);
+    float G   = GeometrySmith(norm, viewDir, lightVec, roughness);
+    // vec3 F    = fresnelSchlick(max(dot(halfway, viewDir), 0.0), F0);
+    vec3 F    = fresnelSchlick(clamp(dot(H, V), 0.0, 1.0), F0);
+
+    vec3 numerator    = NDF * G * F;
+    float denominator = 4.0 * max(dot(N, V), 0.0) * max(dot(N, L), 0.0) + 0.0001;
+    vec3 specular     = numerator / denominator;
+
+    vec3 kS = F;
+
+    vec3 kD = vec3(1.0) - kS;
+    kD *= 1.0 - metallic;
+
+    // add to outgoing radiance Lo
+    float NdotL = max(dot(N, L), 0.0);
+    Lo += (kD * albedo / PI + specular) * radiance * NdotL;
+    // Lo += radiance;
+  }
+
+  vec3 ambient = vec3(0.03) * albedo * ao;
+  vec3 color = ambient + Lo; //ambient + Lo;
+	
+    color = color / (color + vec3(1.0));
+    color = pow(color, vec3(1.0/2.2));
+   
+   FragColor = vec4(color, 1.0);
+  //  FragColor = vec4(1.0);
+  // FragColor = vec4(scene.pointLights[0].position);
+  FragColor = vec4(albedo, 1.0);
+  // FragColor = vec4(pbr.metallic, pbr.roughness, pbr.ao, 1.0);
+  // FragColor = scene.viewPos;
+}
+
+/* The below are from https://learnopengl.com/PBR/Lighting */
+
+vec3 fresnelSchlick(float cosTheta, vec3 F0) {
+  return F0 + (1.0 - F0) * pow(clamp(1.0 - cosTheta, 0.0, 1.0), 5.0);
+}
+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 num   = a2;
+  float denom = (NdotH2 * (a2 - 1.0) + 1.0);
+  denom = PI * denom * denom;
+
+  return num / denom;
+}
+
+float GeometrySchlickGGX(float NdotV, float roughness)
+{
+    float r = (roughness + 1.0);
+    float k = (r*r) / 8.0;
+
+    float num   = NdotV;
+    float denom = NdotV * (1.0 - k) + k;
+	
+    return num / 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;
+}
diff --git a/assets/shaders/pbr_textured.vert b/assets/shaders/pbr_textured.vert
new file mode 100644
index 0000000..40a6f29
--- /dev/null
+++ b/assets/shaders/pbr_textured.vert
@@ -0,0 +1,28 @@
+#version 410 core
+
+// Vertex attributes
+layout(location = 0) in vec3 inPosition;
+layout(location = 1) in vec3 inNormal;
+layout(location = 2) in vec2 inTexCoords;
+
+// Uniforms
+uniform MVP_Matrices {
+  mat4 model; // TODO: make model a push constant/raw uniform
+  mat4 view;
+  mat4 proj;
+} mvp;
+
+// Outputs
+layout(location = 0) out vec3 fragWorldPos;
+layout(location = 1) out vec3 fragNormal;
+layout(location = 2) out vec2 fragTexCoords;
+
+void main() {
+  fragWorldPos = vec3(mvp.model * vec4(inPosition, 1.0));
+  fragNormal = mat3(transpose(inverse(mvp.model))) * inNormal;  
+  // fragNormal = inNormal;
+  
+  fragTexCoords = inTexCoords;
+
+  gl_Position =  mvp.proj * mvp.view * mvp.model * vec4(inPosition, 1.0);
+}