gl.bmx

GLGraphics 640, 480
glewInit()

Local verts : Float[] = [-1.0, -1.0, 0.0, 1.0, -1.0, 0.0, 0.0,  1.0, 0.0]

Local vao : Int
Local vbo : Int

glGenVertexArrays(1, Varptr(vao))
glBindVertexArray(vao)

glGenBuffersARB(1, Varptr(vbo))
glBindBufferARB(GL_ARRAY_BUFFER_ARB, vbo)
glBufferDataARB(GL_ARRAY_BUFFER_ARB, 3 * 3 * 4, verts, GL_STATIC_DRAW)

glEnableVertexAttribArrayARB(0)
glVertexAttribPointerARB(0, 3, GL_FLOAT, GL_FALSE, 0, Null)


Local VshaderCode : String
Local FshaderCode : String

ReadData str$
If str$.ToInt() = 1
	While str$.ToInt() <> 2
		ReadData str$
		VshaderCode = VshaderCode + str
	EndWhile
	While str$.ToInt() <> 99
		ReadData str$
		FshaderCode = FshaderCode + str
	EndWhile
	VshaderCode = Left(VshaderCode, VshaderCode.length-1)
	FshaderCode = Left(FshaderCode, FshaderCode.length-2)
	Print "Vertex Shader: " + VshaderCode
	Print "Fragment Shader: " + FshaderCode
EndIf

Local fs : Int = glCreateShader(GL_FRAGMENT_SHADER)
Local vs : Int = glCreateShader(GL_VERTEX_SHADER)
Local prog : Int = glCreateProgram()

Local vsPtr : Byte Ptr[1]
Local fsPtr : Byte Ptr[1]
vsPtr[0] = VshaderCode.ToCString()
fsPtr[0] = FshaderCode.ToCString()

glShaderSourceARB(vs, 1, vsPtr, Null)
glCompileShaderARB(vs)

glShaderSourceARB(fs, 1, fsPtr, Null)
glCompileShaderARB(fs)

glAttachShader(prog, vs)
glAttachShader(prog, fs)

glLinkProgram(prog)

Repeat
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
	
	glUseProgram(prog)
	glDrawArrays(GL_TRIANGLES, 0, 3)	

	Flip
Until AppTerminate() Or KeyHit(KEY_ESCAPE)

' Vertex Shader
DefData 1, "attribute vec3 position;varying vec3 P;", "void main() {", "gl_Position = vec4(position, 1.0);P=position;" , "}"
' Fragment Shader
DefData 2, "varying vec3 P;", "void main() {", "gl_FragColor = vec4(normalize(P), 1.0); }", 99