Implement shadow mapping pipeline for terrain and models

include/rendering/renderer.hpp

@@ -174,6 +174,18 @@ private:
     void resizePostProcess(int w, int h);
     void shutdownPostProcess();
 
+    // Shadow mapping
+    static constexpr int SHADOW_MAP_SIZE = 2048;
+    uint32_t shadowFBO = 0;
+    uint32_t shadowDepthTex = 0;
+    uint32_t shadowShaderProgram = 0;
+    glm::mat4 lightSpaceMatrix = glm::mat4(1.0f);
+
+    void initShadowMap();
+    void renderShadowPass();
+    uint32_t compileShadowShader();
+    glm::mat4 computeLightSpaceMatrix();
+
     pipeline::AssetManager* cachedAssetManager = nullptr;
     uint32_t currentZoneId = 0;
     std::string currentZoneName;

include/rendering/shader.hpp

@@ -30,6 +30,11 @@ public:
 
     GLuint getProgram() const { return program; }
 
+    // Adopt an externally-created program (no ownership of individual shaders)
+    void setProgram(GLuint prog) { program = prog; }
+    // Release ownership without deleting (caller retains the GL program)
+    void releaseProgram() { program = 0; vertexShader = 0; fragmentShader = 0; }
+
 private:
     bool compile(const std::string& vertexSource, const std::string& fragmentSource);
     GLint getUniformLocation(const std::string& name) const;

include/rendering/terrain_renderer.hpp

@@ -125,6 +125,19 @@ public:
     void setFogEnabled(bool enabled) { fogEnabled = enabled; }
     bool isFogEnabled() const { return fogEnabled; }
 
+    /**
+     * Render terrain geometry into shadow depth map
+     */
+    void renderShadow(GLuint shaderProgram);
+
+    /**
+     * Set shadow map for receiving shadows
+     */
+    void setShadowMap(GLuint depthTex, const glm::mat4& lightSpaceMat) {
+        shadowDepthTex = depthTex; lightSpaceMatrix = lightSpaceMat; shadowEnabled = true;
+    }
+    void clearShadowMap() { shadowEnabled = false; }
+
     /**
      * Get statistics
      */
@@ -187,6 +200,11 @@ private:
 
     // Default white texture (fallback)
     GLuint whiteTexture = 0;
+
+    // Shadow mapping (receiving)
+    GLuint shadowDepthTex = 0;
+    glm::mat4 lightSpaceMatrix = glm::mat4(1.0f);
+    bool shadowEnabled = false;
 };
 
 } // namespace rendering