init commit

src/Shader/DemoShader.cpp

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+//
+// Created by sfd on 25-7-28.
+//
+
+#include "DemoShader.h"
+
+#include <cmath>
+
+void DemoVertexShader(BlinnVaryings& varyings, const BlinnVertex& vertex, const BlinnUniform& uniform)
+{
+    varyings.ClipPos = uniform.MVP * vertex.ModelPosition;
+    varyings.TexCoord = vertex.TexCoord;
+    varyings.WorldPos = uniform.Model * vertex.ModelPosition;
+    varyings.WorldNormal = uniform.ModelNormalToWorld * Math::Vec4{ vertex.ModelNormal, 0.0f};
+}
+
+Math::Vec4 DemoFragmentShader(bool& discard, const BlinnVaryings& varyings, const BlinnUniform& uniform)
+{
+    discard = false;
+
+    const Math::Vec3 cameraPos = uniform.Camera;
+    const Math::Vec3 lightPos = uniform.LightPos;
+    const Math::Vec3 worldPos = varyings.WorldPos;
+
+    Math::Vec3 worldNormal = Math::Normalize(varyings.WorldNormal);
+    const Math::Vec3 viewDir = Math::Normalize(cameraPos - worldPos);
+    const Math::Vec3 lightDir = Math::Normalize(lightPos - worldPos);
+
+    Math::Vec3 halfDir = Math::Normalize(viewDir + lightDir);
+
+    Math::Vec3 ambient = uniform.LightAmbient;
+    Math::Vec3 specularStrength {1.0f, 1.0f, 1.0f};
+    Math::Vec3 diffColor {1.0f , 1.0f , 1.0f};
+    if (uniform.Diffuse)
+    {
+        const Math::Vec2& texCoord = varyings.TexCoord;
+        diffColor = uniform.Diffuse->Sample(texCoord);
+        ambient = ambient * diffColor;
+        if (uniform.Specular)
+            specularStrength = uniform.Specular->Sample(texCoord);
+    }
+
+
+    Math::Vec3 diffuse = std::max(0.0f, Math::Dot(worldNormal, lightDir)) * uniform.LightDiffuse * diffColor;
+    Math::Vec3 specular = (float)pow(std::max(0.0f, Math::Dot(halfDir, worldNormal)), uniform.Shininess) * uniform.LightSPecular * specularStrength;
+
+    Math::Vec3 result = (ambient + diffuse + specular);
+
+    return {result, 1.0f};
+}