basic lighting

inc/engine/shaders.hpp

@@ -17,6 +17,7 @@ public:
     void setInt(const std::string &name, int value) const;
     void setFloat(const std::string &name, float value) const;
     void setMat4(const std::string &name, const glm::mat4 &mat) const;
+    void setVec3(const std::string &name, const glm::vec3 &vec) const;
     ~Shader();
 private:
     const char* read_file(const char* filePath);

shaders/triangle.frag

@@ -1,11 +1,34 @@
 #version 330 core
-
 out vec4 FragColor;
-in vec3 Color; // Input color from the vertex shader
-in vec2 TexCoord; // Input texture coordinate from the vertex shader
+in vec3 FragPos;  
+in vec3 Normal;
+in vec2 TexCoord;
 
+uniform vec3 objectColor;
+uniform vec3 lightColor;
+uniform vec3 lightPos;
+uniform vec3 viewPos;
 uniform sampler2D Texture1;
 
-void main() {
-    FragColor = texture(Texture1, TexCoord);
+void main()
+{
+    // ambient
+    float ambientStrength = 0.1;
+    vec3 ambient = ambientStrength * lightColor;
+  	
+    // diffuse 
+    vec3 norm = normalize(Normal);
+    vec3 lightDir = normalize(lightPos - FragPos);
+    float diff = max(dot(norm, lightDir), 0.0);
+    vec3 diffuse = diff * lightColor;
+
+    // specular
+    float specularStrength = 0.5;
+    vec3 viewDir = normalize(viewPos - FragPos);
+    vec3 reflectDir = normalize(reflect(-lightDir, norm));  
+    float spec = pow(max(dot(viewDir, reflectDir), 0.0), 32.0);
+    vec3 specular = specularStrength * spec * lightColor;
+
+    vec3 result = (ambient + diffuse + specular) * texture(Texture1, TexCoord).rgb;
+    FragColor = vec4(result, 1.0);
 }

shaders/triangle.vert

@@ -3,8 +3,9 @@
 layout(location = 0) in vec3 position; // Vertex position
 layout(location = 1) in vec3 normal;   // Vertex normal
 layout(location = 2) in vec2 texCoord; // Vertex texture coordinate
-out vec3 Color; // Output color to the fragment shader
-out vec2 TexCoord; // Output texture coordinate to the fragment shader
+out vec3 Normal;
+out vec3 FragPos;  
+out vec2 TexCoord;
 
 uniform mat4 model;
 uniform mat4 view;
@@ -12,6 +13,7 @@ uniform mat4 projection;
 
 void main() {
     gl_Position = projection * view * model * vec4(position, 1.0); // Apply transformation matrices
-    Color = normal * 0.5 + 0.5; // Simple coloring based on normal
-    TexCoord = texCoord; // Pass through the texture coordinate
+    FragPos = vec3(model * vec4(position, 1.0));
+    Normal = mat3(transpose(inverse(model))) * normal;
+    TexCoord = texCoord;
 }

shaders/triangle_light_source.frag

@@ -0,0 +1,7 @@
+#version 330 core
+out vec4 FragColor;
+
+void main()
+{
+    FragColor = vec4(1.0); // set all 4 vector values to 1.0
+}

src/engine/shaders.cpp

@@ -92,6 +92,10 @@ void Shader::setMat4(const std::string &name, const glm::mat4 &mat) const {
     glUniformMatrix4fv(glGetUniformLocation(ID, name.c_str()), 1, GL_FALSE, &mat[0][0]);
 }
 
+void Shader::setVec3(const std::string &name, const glm::vec3 &vec) const {
+    glUniform3fv(glGetUniformLocation(ID, name.c_str()), 1, &vec[0]);
+}
+
 Shader::~Shader() {
     if (ID != 0) {
         glDeleteProgram(ID);

src/main.cpp

@@ -1,3 +1,4 @@
+#define GL_GLEXT_PROTOTYPES
 #include "engine/sdl.hpp"
 #include "engine/opengl.hpp"
 #include "engine/obj_loader.hpp"
@@ -10,7 +11,7 @@ int main(int argc, char* argv[]) {
     glEnable(GL_DEPTH_TEST); 
 
     Camera camera(
-        glm::vec3(3.0f, 4.0f, 6.0f), // Position
+        glm::vec3(5.0f, 2.0f, 4.0f), // Position
         glm::vec3(0.0f, 1.0f, 0.0f), // Target
         glm::vec3(0.0f, 1.0f, 0.0f)  // Up vector
     );
@@ -22,17 +23,24 @@ int main(int argc, char* argv[]) {
         100.0f               // Far Plane
     );
 
-    Shader shader_program("shaders/triangle.vert", "shaders/triangle.frag");
+    Shader cubeShader("shaders/triangle.vert", "shaders/triangle.frag");
+    Shader lightShader("shaders/triangle.vert", "shaders/triangle_light_source.frag");
 
-    OBJLoader objLoader("assets/models/Sci-fi_Container_Game.obj");
-    if (!objLoader.isLoaded()) {
+    OBJLoader mainObj("assets/models/Sci-fi_Container_Game.obj");
+    if (!mainObj.isLoaded()) {
+        SDL_Log("Failed to load OBJ model.");
+        return -1;
+    }
+
+    OBJLoader lightObj("assets/models/cube.obj");
+    if (!lightObj.isLoaded()) {
         SDL_Log("Failed to load OBJ model.");
         return -1;
     }
 
     VertexArrayObject VAO;
-    VAO.bufferVertexData(objLoader.getVertexData(), objLoader.getVertexCount() * sizeof(float) * 8);
-    VAO.bufferElementData(objLoader.getIndexData(), objLoader.getIndexCount() * sizeof(unsigned int));
+    VAO.bufferVertexData(mainObj.getVertexData(), mainObj.getVertexCount() * sizeof(float) * 8);
+    VAO.bufferElementData(mainObj.getIndexData(), mainObj.getIndexCount() * sizeof(unsigned int));
     VAO.setAttributePointer(0, 3, GL_FLOAT, false, 8 * sizeof(float), 0); // position
     VAO.setAttributePointer(1, 3, GL_FLOAT, false, 8 * sizeof(float), 3 * sizeof(float)); // normal
     VAO.setAttributePointer(2, 2, GL_FLOAT, false, 8 * sizeof(float), 6 * sizeof(float)); // texCoord
@@ -40,6 +48,15 @@ int main(int argc, char* argv[]) {
     Texture texture("assets/textures/Sci-fi_Container_Base_Color.png");
     texture.bind(GL_TEXTURE0);
 
+    VertexArrayObject lightCubeVAO;
+    lightCubeVAO.bufferVertexData(lightObj.getVertexData(), lightObj.getVertexCount() * sizeof(float) * 8);
+    lightCubeVAO.bufferElementData(lightObj.getIndexData(), lightObj.getIndexCount() * sizeof(unsigned int));
+    lightCubeVAO.setAttributePointer(0, 3, GL_FLOAT, false, 8 * sizeof(float), 0); // position
+    lightCubeVAO.setAttributePointer(1, 3, GL_FLOAT, false, 8 * sizeof(float), 3 * sizeof(float)); // normal
+    lightCubeVAO.setAttributePointer(2, 2, GL_FLOAT, false, 8 * sizeof(float), 6 * sizeof(float)); // texCoord
+
+    glm::vec3 lightPos(6.0f, 3.0f, 3.0f);
+
     window.setPosition(SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED);
     window.showWindow();
 
@@ -49,13 +66,28 @@ int main(int argc, char* argv[]) {
         glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
-        shader_program.use();
-        shader_program.setMat4("view", camera.getViewMatrix());
-        shader_program.setMat4("projection", camera.getProjectionMatrix());
-        shader_program.setMat4("model", glm::mat4(1.0f));
+        cubeShader.use();
+        cubeShader.setMat4("view", camera.getViewMatrix());
+        cubeShader.setMat4("projection", camera.getProjectionMatrix());
+        cubeShader.setMat4("model", glm::mat4(1.0f));
+        cubeShader.setVec3("objectColor", glm::vec3(1.0f, 0.5f, 0.31f));
+        cubeShader.setVec3("lightColor", glm::vec3(1.0f, 1.0f, 1.0f));
+        cubeShader.setVec3("lightPos", lightPos);
+        cubeShader.setVec3("viewPos", camera.getPosition());
 
         VAO.draw();
 
+        glm::mat4 model = glm::mat4(1.0f);
+        model = glm::translate(model, lightPos);
+        model = glm::scale(model, glm::vec3(0.2f)); 
+
+        lightShader.use();
+        lightShader.setMat4("view", camera.getViewMatrix());
+        lightShader.setMat4("projection", camera.getProjectionMatrix());
+        lightShader.setMat4("model", model);
+
+        lightCubeVAO.draw();
+
         glContext.swapBuffers();
     }