checkeboard pattern

src/main.c

@@ -129,14 +129,14 @@ void init(void) {
 	 */    
 
 	GLfloat vertices[] = {
-		// X    // Y   // vertValue
-		-0.75f, -0.1f, 0.0f,
-		-0.75f,  0.1f, 0.0f,
-		 0.75f,  0.1f, 1.0f,
+		// X   // Y   // tX  // tY
+		-1.0f, -1.0f, 0.0f,  0.0f,
+		-1.0f,  1.0f, 0.0f,  1.0f,
+		 1.0f,  1.0f, 1.0f,  1.0f,
 
-		-0.75f, -0.1f, 0.0f,
-		 0.75f, -0.1f, 1.0f,
-		 0.75f,  0.1f, 1.0f
+		-1.0f, -1.0f, 0.0f,  0.0f,
+		 1.0f, -1.0f, 1.0f,  0.0f,
+		 1.0f,  1.0f, 1.0f,  1.0f
 	};
 
 	DEBUG("Creating vertext buffer");
@@ -158,12 +158,12 @@ void init(void) {
 		2, // number of values to read
 		GL_FLOAT, // type of value
 		GL_FALSE, // if values are normalised
-		3 * sizeof(GLfloat), // stride - distance between vertices
+		4 * sizeof(GLfloat), // stride - distance between vertices
 		0 // start offset
 	);
 	glEnableVertexAttribArray(0);
 
-	glVertexAttribPointer(1, 1, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat), (void*)(2*sizeof(GLfloat)));
+	glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat), (void*)(2*sizeof(GLfloat)));
 	glEnableVertexAttribArray(1);
 
 	glBindBuffer(GL_ARRAY_BUFFER, 0);
@@ -190,15 +190,7 @@ void draw(void) {
 
 	glBindVertexArray(vertexArrayObject);
 
-	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);
-	}
+	glDrawArrays(GL_TRIANGLES, 0, 6);
 
 }
 

src/shaders/fragment.glsl

@@ -1,31 +1,8 @@
 #version 330 core
-in float fragValue;
-flat in int pattern;
+in vec2 fragValue;
 void main() {
 	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);
-	}
+	gl_FragColor = vec4(vec3(step(0, sin(fragValue.x * 3.14 * 4) * sin(fragValue.y * 3.14 * 4))), 1.0);
 }

src/shaders/vertex.glsl

@@ -1,15 +1,10 @@
 #version 330 core
 layout (location = 0) in vec2 aPosition;
-layout (location = 1) in float vertValue;
+layout (location = 1) in vec2 vertValue;
 
-uniform float uYPosition;
-uniform int uPattern;
-
-out float fragValue;
-flat out int pattern;
+out vec2 fragValue;
 
 void main() {
-	pattern = uPattern;
 	fragValue = vertValue;
-	gl_Position = vec4(aPosition.x, aPosition.y + uYPosition, 0.0, 1.0);
+	gl_Position = vec4(aPosition, 0.0, 1.0);
 }