Got through the requisite amount of invisible pain to get something onto my GL display. But clearly this is factored in entirely the wrong way. Work to do.

OSBindings/Mac/Clock Signal/Atari2600.mm

@@ -8,7 +8,31 @@
 
 #import "Atari2600.h"
 #import "Atari2600.hpp"
-#import <OpenGL/gl.h>
+#import <OpenGL/gl3.h>
+
+const char *vertexShader =
+	"#version 150\n"
+	"\n"
+	"in vec2 position;\n"
+	"\n"
+	"out vec4 colour;\n"
+	"\n"
+	"void main (void)\n"
+	"{\n"
+		"colour = vec4(position, 0.0, 1.0);\n"
+		"gl_Position = vec4(position, 0.0, 1.0);\n"
+	"}\n";
+
+const char *fragmentShader =
+	"#version 150\n"
+	"\n"
+	"in vec4 colour;\n"
+	"out vec4 fragColour;\n"
+	"\n"
+	"void main(void)\n"
+	"{\n"
+		"fragColour = colour;\n"
+	"}\n";
 
 @interface CSAtari2600 (Callbacks)
 - (void)crtDidEndFrame:(Outputs::CRTFrame *)frame;
@@ -25,6 +49,11 @@ struct Atari2600CRTDelegate: public Outputs::CRT::CRTDelegate {
 
 	dispatch_queue_t _serialDispatchQueue;
 	Outputs::CRTFrame *_queuedFrame;
+
+	GLuint _vertexShader, _fragmentShader;
+	GLuint _shaderProgram;
+
+	GLuint _arrayBuffer, _vertexArray;
 }
 
 - (void)crtDidEndFrame:(Outputs::CRTFrame *)frame {
@@ -41,12 +70,55 @@ struct Atari2600CRTDelegate: public Outputs::CRT::CRTDelegate {
 	});
 }
 
+- (GLuint)compileShader:(const char *)source type:(GLenum)type
+{
+	GLuint shader = glCreateShader(type);
+	glShaderSource(shader, 1, &source, NULL);
+	glCompileShader(shader);
+	return shader;
+}
+
 - (void)draw {
 
+	if(!_shaderProgram)
+	{
+		_shaderProgram = glCreateProgram();
+		_vertexShader = [self compileShader:vertexShader type:GL_VERTEX_SHADER];
+		_fragmentShader = [self compileShader:fragmentShader type:GL_FRAGMENT_SHADER];
+
+		glAttachShader(_shaderProgram, _vertexShader);
+		glAttachShader(_shaderProgram, _fragmentShader);
+		glLinkProgram(_shaderProgram);
+
+		glGenVertexArrays(1, &_vertexArray);
+		glBindVertexArray(_vertexArray);
+		glGenBuffers(1, &_arrayBuffer);
+		glBindBuffer(GL_ARRAY_BUFFER, _arrayBuffer);
+
+		GLfloat vertices[] = {
+			0.0f, 0.0f,
+			0.5f, 0.0f,
+			0.5f, 0.6f,
+			0.0f, 0.5f
+		};
+
+		glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+	}
+
 	if(_queuedFrame)
 	{
 		glClearColor(1.0, 0.0, 0.0, 1.0);
 		glClear(GL_COLOR_BUFFER_BIT);
+
+		glUseProgram(_shaderProgram);
+
+		GLint position = glGetAttribLocation(_shaderProgram, "position");
+
+		glEnableVertexAttribArray(position);
+		glVertexAttribPointer(position, 2, GL_FLOAT, GL_FALSE, 0, (void *)0);
+
+		glDrawArrays(GL_LINES, 0, 4);
+
 /*		printf("\n\n===\n\n");
 		int c = 0;
 		for(int run = 0; run < _queuedFrame->number_of_runs; run++)