internal ShaderProgram(GraphicsLibrary gl, string vertexShaderSource, string fragmentShaderSource)
{
program = gl.CreateProgram();
var vertexShader = CompileShader(gl, ShaderType.Vertex, vertexShaderSource);
var fragmentShader = CompileShader(gl, ShaderType.Fragment, fragmentShaderSource);
LinkProgram(gl);
gl.DeleteShader(vertexShader);
gl.DeleteShader(fragmentShader);
}
internal Shader(GraphicsLibrary gl, string vertexShaderSource, string fragmentShaderSource, bool useTexture)
{
program = new ShaderProgram(gl, vertexShaderSource, fragmentShaderSource);
program.Use(gl);
ColorLocation = program.GetUniformLocation(gl, "color");
projectionLocation = program.GetUniformLocation(gl, "projection");
if (useTexture)
{
var sampler = program.GetUniformLocation(gl, "sampler");
program.Uniform1i(gl, sampler, 0);
}
}
private unsafe uint CompileShader(GraphicsLibrary gl, ShaderType type, string source)
{
var shader = gl.CreateShader(type);
var header = GetShaderHeader(gl);
var byteCount = Encoding.UTF8.GetMaxByteCount(header.Length);
byteCount += Encoding.UTF8.GetMaxByteCount(source.Length);
if (byteCount + 1 > byteBuffer.Length)
{
byteBuffer = new byte[byteCount + 1];
}
byteCount = Encoding.UTF8.GetBytes(header, 0, header.Length, byteBuffer, 0);
byteCount += Encoding.UTF8.GetBytes(source, 0, source.Length, byteBuffer, byteCount);
byteBuffer[byteCount] = 0;
fixed(byte *p = byteBuffer)
{
byte *t = p;
gl.ShaderSource(shader, 1, &t, null);
}
gl.CompileShader(shader);
int len;
gl.GetShaderiv(shader, ShaderParameter.InfoLogLength, &len);
if (len > 1)
{
var buffer = new byte[len];
fixed(byte *p = buffer)
{
gl.GetShaderInfoLog(shader, len, &len, p);
Console.WriteLine("Shader Compiler message: " + Marshal.PtrToStringAnsi(new IntPtr(p)));
}
}
int cs;
gl.GetShaderiv(shader, ShaderParameter.CompileStatus, &cs);
if (cs == 0)
{
gl.DeleteShader(shader);
throw new InvalidOperationException("Shader compilation error");
}
gl.AttachShader(program, shader);
return(shader);
}
private static unsafe string GetShaderHeader(GraphicsLibrary gl)
{
if (shaderHeader == null)
{
string?s = Marshal.PtrToStringAnsi(new IntPtr(gl.GetString(StringParameter.ShadingLanguageVersion)));
if (!string.IsNullOrEmpty(s) && s.StartsWith("4."))
{
shaderHeader = $"#version 4{s.Substring(2, 2)} core\n";
}
else
{
shaderHeader =
@"#version 300 es
#ifdef GL_FRAGMENT_PRECISION_HIGH
precision highp float;
#else
precision mediump float;
#endif
";
}
}
return(shaderHeader);
}
internal unsafe void LinkProgram(GraphicsLibrary gl)
{
gl.LinkProgram(program);
int ls;
gl.GetProgramiv(program, ProgramParameter.LinkStatus, &ls);
if (ls == 0)
{
int len;
gl.GetProgramiv(program, ProgramParameter.InfoLogLength, &len);
if (len > 1)
{
var buffer = new byte[len];
fixed(byte *p = buffer)
{
gl.GetProgramInfoLog(program, len, &len, p);
Console.WriteLine("Shader link message: " + Marshal.PtrToStringAnsi(new IntPtr(p)));
}
}
gl.DeleteProgram(program);
throw new InvalidOperationException("Shader link error");
}
}
internal void SetColor(GraphicsLibrary gl, float red, float green, float blue, float alpha) => program.Uniform4f(gl, ColorLocation, red, green, blue, alpha);
internal void SetColor(GraphicsLibrary gl, RgbaColor color) => program.Uniform4f(gl, ColorLocation, color.Red / 255f, color.Green / 255f, color.Blue / 255f, color.Alpha / 255f);
internal void SetProjection(GraphicsLibrary gl, Matrix4x4 projection) => program.UniformMatrix(gl, projectionLocation, projection);
internal void Use(GraphicsLibrary gl) => program.Use(gl);
internal void Delete(GraphicsLibrary gl) => program.Delete(gl);
internal void Uniform4f(GraphicsLibrary gl, int uniform, float f0, float f1, float f2, float f3) => gl.Uniform4f(uniform, f0, f1, f2, f3);
internal void Uniform1i(GraphicsLibrary gl, int uniform, int i0) => gl.Uniform1i(uniform, i0);
internal void Use(GraphicsLibrary gl) => gl.UseProgram(program);
internal void Delete(GraphicsLibrary gl) => gl.DeleteProgram(program);