gistfile1.c

#define WIN32_LEAN_AND_MEAN
#define WIN32_EXTRA_LEAN
#include <windows.h>
#include <mmsystem.h>
#include <GL/gl.h>
#include "glext.h"

#define	XRES 1280
#define YRES 720

// fragment shader
static const char *fragmentShader =
"float t=gl_Color.x*100;"
"void main(){"
"vec2 uv=gl_FragCoord.xy/500;"
"float c=sin(t+uv.x*3)+sin(t+uv.y*5)+sin((t+uv.x+uv.y)*4);"
"gl_FragColor=vec4(vec3(sin(c),sqrt(c),cos(c)),1);"
"}";

// pixel format descriptor
static PIXELFORMATDESCRIPTOR pfd = { 0, 0, PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER };

// screen settings (uncomment for proper screen control)
//static DEVMODE screenSettings = { { 0 }, 0, 0, sizeof(DEVMODE), 0,
//DM_PELSWIDTH | DM_PELSHEIGHT,
//{ 0 }, 0, 0, 0, 0, 0, { 0 }, 0, 0, XRES, YRES};

//----------------------------------------------------------------------------

void main() {
	// full screen (uncomment for proper screen control)
	//ChangeDisplaySettings(&screenSettings, CDS_FULLSCREEN);

	// create windows
	const HDC hDC = GetDC(CreateWindowA((LPCSTR)0xC018, 0, WS_POPUP | WS_VISIBLE | WS_MAXIMIZE, 0, 0, 0, 0, 0, 0, 0, 0));

    // init opengl
    SetPixelFormat(hDC, ChoosePixelFormat(hDC, &pfd), &pfd);
    wglMakeCurrent(hDC, wglCreateContext(hDC));
	ShowCursor(NULL);

	// midi
	static HMIDIOUT out;
	midiOutOpen(&out, 0, 0, 0, CALLBACK_NULL);					// open MIDI output
	midiOutShortMsg(out, 0x7eC0);								// change instrument
	midiOutShortMsg(out, 0x7f2490);								// play a note

    // create shader
	const int ps = ((PFNGLCREATESHADERPROGRAMVPROC)wglGetProcAddress("glCreateShaderProgramv"))(GL_FRAGMENT_SHADER, 1, &fragmentShader);
	((PFNGLUSEPROGRAMPROC)wglGetProcAddress("glUseProgram"))(ps);
	
	const int startTime = timeGetTime();						// get starting time
	int time;

    do {
		time = (timeGetTime() - startTime);						// calculate current time
		glColor3us (time, 0, 0);								// pass time to shader through gl_Color
		glRects(-1,-1,1,1);										// draw full screen rectangle
		SwapBuffers(hDC);										// swap buffer call to refresh screen
		PeekMessageA(0, 0, 0, 0, PM_REMOVE);					// Remove error message to prevent busy cursor
	} while (time < 30000 && !GetAsyncKeyState(VK_ESCAPE));		// exit after time or escape key press

    ExitProcess(NULL);

}