Merge pull request #25 from Pilzschaf/tutorial29-lighting

Basic lighting

Author: Pilzschaf

camera.h

@@ -17,6 +17,10 @@ class Camera {
         return viewProj;
     }
 
+    glm::mat4 getView() {
+        return view;
+    }
+
     virtual void update() {
         viewProj = projection * view;
     }

main.cpp

@@ -131,6 +131,8 @@ int main(int argc, char** argv) {
 	glm::mat4 modelViewProj = camera.getViewProj() * model;
 
 	int modelViewProjMatrixLocation = GLCALL(glGetUniformLocation(shader.getShaderId(), "u_modelViewProj"));
+	int modelViewLocation = GLCALL(glGetUniformLocation(shader.getShaderId(), "u_modelView"));
+	int invModelViewLocation = GLCALL(glGetUniformLocation(shader.getShaderId(), "u_invModelView"));
 
 	// Wireframe
 	//glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
@@ -231,10 +233,14 @@ int main(int argc, char** argv) {
 		camera.update();
 		model = glm::rotate(model, 1.0f*delta, glm::vec3(0, 1, 0));
 		modelViewProj = camera.getViewProj() * model;
+		glm::mat4 modelView = camera.getView() * model;
+		glm::mat4 invModelView = glm::transpose(glm::inverse(modelView));
 
 		vertexBuffer.bind();
 		indexBuffer.bind();
 		GLCALL(glUniformMatrix4fv(modelViewProjMatrixLocation, 1, GL_FALSE, &modelViewProj[0][0]));
+		GLCALL(glUniformMatrix4fv(modelViewLocation, 1, GL_FALSE, &modelView[0][0]));
+		GLCALL(glUniformMatrix4fv(invModelViewLocation, 1, GL_FALSE, &invModelView[0][0]));
 		GLCALL(glDrawElements(GL_TRIANGLES, numIndices, GL_UNSIGNED_INT, 0));
 		indexBuffer.unbind();
 		vertexBuffer.unbind();

shaders/basic.fs

@@ -2,9 +2,21 @@
 
 layout(location = 0) out vec4 f_color;
 
-in vec4 v_color;
+in vec3 v_normal;
+in vec3 v_position;
 
 void main()
 {
-    f_color = v_color;
+    // Vector from fragment to camera (camera always at 0,0,0)
+    vec3 view = normalize(-v_position);
+    vec3 light = normalize(vec3(1.0f, 1.0f, 1.0f));
+    vec3 normal = normalize(v_normal);
+    vec3 color = vec3(0.4f, 0.2f, 0.1f);
+    vec3 reflection = reflect(-light, normal);
+
+    vec3 ambient = color * 0.2;
+    vec3 diffuse = max(dot(normal, light), 0.0) * color;
+    vec3 specular = pow(max(dot(reflection, view), 0.0), 4.0) * color;
+
+    f_color = vec4(ambient + diffuse + specular, 1.0f);
 }

shaders/basic.vs

@@ -3,12 +3,16 @@
 layout(location = 0) in vec3 a_position;
 layout(location = 1) in vec3 a_normal;
 
-out vec4 v_color;
+out vec3 v_normal;
+out vec3 v_position;
 
 uniform mat4 u_modelViewProj;
+uniform mat4 u_modelView;
+uniform mat4 u_invModelView;
 
 void main()
 {
     gl_Position = u_modelViewProj * vec4(a_position, 1.0f);
-    v_color = vec4(a_normal, 1.0f);
+    v_normal = mat3(u_invModelView) * a_normal;
+    v_position = vec3(u_modelView * vec4(a_position, 1.0f));
 }

shaders_old/basic.fs

@@ -1,8 +1,19 @@
 #version 120
 
-varying vec4 v_color;
+varying vec3 v_normal;
+varying vec3 v_position;
 
 void main()
 {
-    gl_FragColor = v_color;
+    vec3 view = normalize(-v_position);
+    vec3 light = normalize(vec3(1.0f, 1.0f, 1.0f));
+    vec3 normal = normalize(v_normal);
+    vec3 color = vec3(0.4f, 0.2f, 0.1f);
+    vec3 reflection = reflect(-light, normal);
+
+    vec3 ambient = color * 0.2;
+    vec3 diffuse = max(dot(normal, light), 0.0) * color;
+    vec3 specular = pow(max(dot(reflection, view), 0.0), 4.0) * color;
+
+    gl_FragColor = vec4(ambient + diffuse + specular, 1.0f);
 }

shaders_old/basic.vs

@@ -3,12 +3,16 @@
 attribute vec3 a_position;
 attribute vec3 a_normal;
 
-varying vec4 v_color;
+varying vec3 v_normal;
+varying vec3 v_position;
 
 uniform mat4 u_modelViewProj;
+uniform mat4 u_modelView;
+uniform mat4 u_invModelView;
 
 void main()
 {
     gl_Position = u_modelViewProj * vec4(a_position, 1.0f);
-    v_color = vec4(a_normal, 1.0f);
+    v_normal = mat3(u_invModelView) * a_normal;
+    v_position = vec3(u_modelView * vec4(a_position, 1.0f));
 }