u03-2

src/main.c

@@ -129,81 +129,14 @@ void init(void) {
 	 */    
 
 	GLfloat vertices[] = {
-		// X  // Y
+		// X    // Y   // vertValue
+		-0.75f, -0.1f, 0.0f,
+		-0.75f,  0.1f, 0.0f,
+		 0.75f,  0.1f, 1.0f,
 
-		// left vertical bar
-		-0.35f, -0.6f,
-		-0.35f, 0.6f,
-		-0.2f, 0.6f,
-
-		-0.35f, -0.6f,
-		-0.2f, 0.6f,
-		-0.2f, -0.6f,
-
-		// right vertical bar
-		0.35f, -0.6f,
-		0.35f, 0.6f,
-		0.2f, 0.6f,
-
-		0.35f, -0.6f,
-		0.2f, 0.6f,
-		0.2f, -0.6f,
-
-		// middle bar
-		-0.2f, -0.1f,
-		-0.2f, 0.1f,
-		0.2f, 0.1f,
-
-		-0.2f, -0.1f,
-		0.2f, 0.1f,
-		0.2f, -0.1f,
-
-		// bottom bar
-		-0.35f, -0.7f,
-		-0.35f, -0.9f,
-		0.35f, -0.9f,
-
-		-0.35f, -0.7f,
-		0.35f, -0.9f,
-		0.35f, -0.7f
-	};
-
-	GLfloat colors[] = {
-		// R  // G  // B
-		1.0f, 0.0f, 0.0f,
-		1.0f, 0.0f, 0.3f,
-		1.0f, 0.3f, 0.0f,
-
-		1.0f, 0.3f, 0.3f,
-		1.0f, 0.3f, 0.6f,
-		1.0f, 0.6f, 0.3f,
-
-
-		0.0f, 1.0f, 0.0f,
-		0.0f, 1.0f, 0.3f,
-		0.3f, 1.0f, 0.0f,
-
-		0.3f, 1.0f, 0.3f,
-		0.3f, 1.0f, 0.6f,
-		0.6f, 1.0f, 0.3f,
-
-
-		0.3f, 0.3f, 1.0f,
-		0.3f, 0.6f, 1.0f,
-		0.6f, 0.3f, 1.0f,
-
-		0.3f, 0.3f, 1.0f,
-		0.3f, 0.6f, 1.0f,
-		0.6f, 0.3f, 1.0f,
-
-
-		1.0f, 1.0f, 0.0f,
-		1.0f, 1.0f, 0.1f,
-		1.0f, 1.0f, 0.2f,
-
-		1.0f, 1.0f, 0.7f,
-		1.0f, 1.0f, 0.8f,
-		1.0f, 1.0f, 0.9f
+		-0.75f, -0.1f, 0.0f,
+		 0.75f, -0.1f, 1.0f,
+		 0.75f,  0.1f, 1.0f
 	};
 
 	DEBUG("Creating vertext buffer");
@@ -213,13 +146,6 @@ void init(void) {
 	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
 	glBindBuffer(GL_ARRAY_BUFFER, 0);
 
-	DEBUG("Creating colour buffer");
-	GLuint colorBuffer;
-	glGenBuffers(1, &colorBuffer);
-	glBindBuffer(GL_ARRAY_BUFFER, colorBuffer);
-	glBufferData(GL_ARRAY_BUFFER, sizeof(colors), colors, GL_STATIC_DRAW);
-	glBindBuffer(GL_ARRAY_BUFFER, 0);
-
 	DEBUG("Creating vertex array object");
 	// create vertex array object
 	glGenVertexArrays(1, &vertexArrayObject);
@@ -232,17 +158,14 @@ void init(void) {
 		2, // number of values to read
 		GL_FLOAT, // type of value
 		GL_FALSE, // if values are normalised
-		2 * sizeof(GLfloat), // stride - distance between vertices
+		3 * sizeof(GLfloat), // stride - distance between vertices
 		0 // start offset
 	);
 	glEnableVertexAttribArray(0);
 
-	// vertex color data
-	glBindBuffer(GL_ARRAY_BUFFER, colorBuffer);
-	glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat), 0);
+	glVertexAttribPointer(1, 1, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat), (void*)(2*sizeof(GLfloat)));
 	glEnableVertexAttribArray(1);
 
-
 	glBindBuffer(GL_ARRAY_BUFFER, 0);
 	glBindVertexArray(0);
 
@@ -265,11 +188,18 @@ void draw(void) {
 	glClear(GL_COLOR_BUFFER_BIT);
 	glUseProgram(program);
 
-	GLuint positionLocation = glGetUniformLocation(program, "uPosition");
-	glUniform2f(positionLocation, cos(currentHue * 2 * M_PI) * 0.2f, sin(currentHue * 2 * M_PI) * 0.2f);
-
 	glBindVertexArray(vertexArrayObject);
-	glDrawArrays(GL_TRIANGLES, 0, 48);
+
+	GLuint yPositionLocation = glGetUniformLocation(program, "uYPosition");
+	GLuint patternLocation = glGetUniformLocation(program, "uPattern");
+
+	for (int i = 0; i < 5; i++) {
+		glUniform1f(yPositionLocation, i / 4.0f * -1.4f + 0.7f);
+		glUniform1i(patternLocation, i);
+
+		glDrawArrays(GL_TRIANGLES, 0, 6);
+	}
+
 }
 
 void framebuffer_size_callback(GLFWwindow* window, int width, int height) {

src/shaders/fragment.glsl

@@ -1,5 +1,31 @@
 #version 330 core
-in vec3 vertexColor;
+in float fragValue;
+flat in int pattern;
 void main() {
-	gl_FragColor = vec4(vertexColor, 1.0);
+	vec4 fragColor1 = vec4(1.0, 0.0, 0.0, 1.0);
+	vec4 fragColor2 = vec4(0.0, 1.0, 0.0, 1.0);
+	switch (pattern) {
+	case 0:
+		gl_FragColor = mix(fragColor1, fragColor2, fragValue);
+		break;
+
+	case 1:
+		gl_FragColor = mix(fragColor1, fragColor2, step(0.5, fragValue));
+		break;
+
+	case 2:
+		gl_FragColor = mix(fragColor1, fragColor2, smoothstep(0.4, 0.6, fragValue));
+		break;
+
+	case 3:
+		gl_FragColor = mix(fragColor1, fragColor2, sin(fragValue * 4 * 3.14159) * 0.5 + 0.5);
+		break;
+
+	case 4:
+		gl_FragColor = mix(fragColor1, fragColor2, step(0.5, sin(fragValue * 4 * 3.14159) * 0.5 + 0.5));
+		break;
+
+	default:
+		gl_FragColor = vec4(0.0);
+	}
 }

src/shaders/vertex.glsl

@@ -1,11 +1,15 @@
 #version 330 core
 layout (location = 0) in vec2 aPosition;
-layout (location = 1) in vec3 aColor;
-uniform vec2 uPosition;
+layout (location = 1) in float vertValue;
 
-out vec3 vertexColor;
+uniform float uYPosition;
+uniform int uPattern;
+
+out float fragValue;
+flat out int pattern;
 
 void main() {
-	vertexColor = aColor;
-	gl_Position = vec4(uPosition + aPosition, 0.0, 1.0);
+	pattern = uPattern;
+	fragValue = vertValue;
+	gl_Position = vec4(aPosition.x, aPosition.y + uYPosition, 0.0, 1.0);
 }