projection

src/main.c

@@ -24,6 +24,8 @@ GLuint indexBuffer;
 GLuint initialWindowWidth = 800;
 GLuint initialWindowHeight = 600;
 
+GLfloat aspect;
+
 int frameCount = 0;
 struct timespec last_time, current_time;
 
@@ -228,24 +230,33 @@ void draw(void) {
 
 	mat4 transformMatrix;
 	vec3 scale = {0.2f, 0.2f, 0.2f};
+	vec3 position = {0.0f, 0.0f, -1.0f};
 	mat4Identity(transformMatrix);
 	mat4Scale(transformMatrix, transformMatrix, scale);
 	
 	// mat4RotateZ(transformMatrix, transformMatrix, currentHue * PI * 2);
 	// mat4RotateY(transformMatrix, transformMatrix, currentHue * PI * 2);
 
+	mat4Translate(transformMatrix, transformMatrix, position);
+	
 	mat4 viewMatrix;
 	mat4Identity(viewMatrix);
 	vec3 cameraPos = {0.0f, sin(currentHue * PI * 2), 0.0f};
-	vec3 cameraLookAt = {0.0f, 0.0f, -1.0f};
+	vec3 cameraLookAt = {0.0f, sin(currentHue * PI * 2), -1.0f};
 	vec3 cameraUp = {0.0f, 1.0f, 0.0f};
 	mat4BuildLookAt(viewMatrix, cameraPos, cameraLookAt, cameraUp);
 
-	GLuint transformLocation = glGetUniformLocation(program, "uTransform");
-	glUniformMatrix4fv(transformLocation, 1, GL_FALSE, transformMatrix);
+	mat4 modelViewMatrix;
+	mat4Multiply(modelViewMatrix, viewMatrix, transformMatrix);
 
-	GLuint viewLocation = glGetUniformLocation(program, "uView");
-	glUniformMatrix4fv(viewLocation, 1, GL_FALSE, viewMatrix);
+	GLuint modelViewLocation = glGetUniformLocation(program, "uModelView");
+	glUniformMatrix4fv(modelViewLocation, 1, GL_FALSE, modelViewMatrix);
+
+	mat4 projectionMatrix;
+	mat4BuildPerspective(projectionMatrix, 60 * M_PI / 180, aspect, 0.1, 10);
+
+	GLuint projectionLocation = glGetUniformLocation(program, "uProjection");
+	glUniformMatrix4fv(projectionLocation, 1, GL_FALSE, projectionMatrix);
 
 	glBindVertexArray(vertexArrayObject);
 	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer);
@@ -254,6 +265,7 @@ void draw(void) {
 
 void framebuffer_size_callback(GLFWwindow* window, int width, int height) {
 	glViewport(0, 0, width, height);
+	aspect = (float)width / height;
 }
 
 int main(int argc, char const *argv[])
@@ -276,6 +288,7 @@ int main(int argc, char const *argv[])
 	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
 
 	GLFWwindow *window = glfwCreateWindow(initialWindowWidth, initialWindowHeight, "CG1", NULL, NULL);
+	aspect = (float)initialWindowWidth / initialWindowHeight;
 	if (!window) {
 		FATAL("Failed to open window");
 		glfwTerminate();

src/matrix-math.c

@@ -180,4 +180,28 @@ void mat4BuildLookAt(mat4 out, vec3 eye, vec3 look, vec3 up) {
 	out[1] = v[0]; out[5] = v[1]; out[9]  = v[2]; out[13] = t[1];
 	out[2] = n[0]; out[6] = n[1]; out[10] = n[2]; out[14] = t[2];
 	out[3] = 0;    out[7] = 0;    out[11] = 0;    out[15] = 1;
+}
+
+void mat4BuildProjection(mat4 out, GLfloat r, GLfloat l, GLfloat t, GLfloat b, GLfloat n, GLfloat f) {
+	mat4Identity(out);
+
+	out[0] = 2.0f / (r - l);
+	out[5] = 2.0f / (t - b);
+
+	out[8] = 1.0f / n * (r + l) / (r - l);
+	out[9] = 1.0f / n * (t + b) / (t - b);
+	out[10] = -1.0f / n * (f + n) / (f - n);
+	out[11] = -1.0f / n;
+
+	out[14] = - 2.0f * f / (f - n);
+}
+
+void mat4BuildPerspective(mat4 out, GLfloat fovy, GLfloat aspect, GLfloat n, GLfloat f) {
+	GLfloat t = n * tan(0.5f * fovy);
+	GLfloat b = -t;
+
+	GLfloat r = aspect * t;
+	GLfloat l = -r;
+
+	mat4BuildProjection(out, r, l, t, b, n, f);
 }

src/matrix-math.h

@@ -23,7 +23,8 @@ extern void mat4RotateX(mat4 out, mat4 in, GLfloat a);
 extern void mat4RotateY(mat4 out, mat4 in, GLfloat a);
 extern void mat4RotateZ(mat4 out, mat4 in, GLfloat a);
 extern void mat4BuildLookAt(mat4 out, vec3 eye, vec3 center, vec3 up);
-extern void mat4BuildProjection(mat4 out, GLfloat r, GLfloat l, GLfloat t, GLfloat b, GLfloat f, GLfloat n);
+extern void mat4BuildProjection(mat4 out, GLfloat r, GLfloat l, GLfloat t, GLfloat b, GLfloat n, GLfloat f);
+extern void mat4BuildPerspective(mat4 out, GLfloat fovy, GLfloat aspect, GLfloat n, GLfloat f);
 
 extern void vec3Subtract(vec3 out, vec3 a, vec3 b);
 extern void vec3CrossProduct(vec3 out, vec3 a, vec3 b);

src/shaders/vertex.glsl

@@ -1,11 +1,11 @@
 #version 330 core
 layout (location = 0) in vec3 aPosition;
-uniform mat4 uTransform;
-uniform mat4 uView;
+uniform mat4 uModelView;
+uniform mat4 uProjection;
 
 out vec3 vertexColor;
 
 void main() {
 	vertexColor = vec3(1.0, 0.1, 0.1);
-	gl_Position = uView * uTransform * vec4(aPosition, 1.0);
+	gl_Position = uProjection * uModelView * vec4(aPosition, 1.0);
 }