public void DrawImage(GlImage image, float x, float y, float width, float height)
{
DrawImage(image, x, y, width, height, 0, 0, image.Width, image.Height);
}
public void DrawImage(GlImage image, RectangleF r, RectangleF ir)
{
DrawImage(image, r.X, r.Y, r.Width, r.Height, ir.X, ir.Y, ir.Width, ir.Height);
}
public void DrawImage(GlImage image, float x, float y, float w, float h, float ix, float iy, float iw, float ih)
{
if (ix < 0)
{
x += -w * ix / iw;
ix = 0;
}
if (ix + iw > image.Width)
{
w -= (ix + iw - image.Width) * w / iw;
iw = image.Width - ix;
}
if (iy < 0)
{
y += -h * iy / ih;
iy = 0;
}
if (iy + ih > image.Height)
{
h -= (iy + ih - image.Height) * h / ih;
ih = image.Height - iy;
}
Gl.UseProgram(image.ShaderProgram);
Gl.ActiveTexture(Gl.GL_TEXTURE0);
Gl.BindTexture(Gl.GL_TEXTURE_2D, image.Id);
Gl.Uniform1(Gl.GetUniformLocation(image.ShaderProgram, "tex"), 0);
var vert = (uint)Gl.GetAttribLocation(image.ShaderProgram, "vert");
var tvert = (uint)Gl.GetAttribLocation(image.ShaderProgram, "vertTexCoord");
var projectionMatrix = new float[16];
Gl.GetFloat(Gl.GL_PROJECTION_MATRIX, projectionMatrix);
Gl.UniformMatrix4(Gl.GetUniformLocation(image.ShaderProgram, "projectionMatrix"), 1, false,
projectionMatrix);
Gl.PolygonMode(Gl.GL_FRONT, Gl.GL_FILL);
Gl.Color(Color.Transparent);
Gl.Enable(Gl.GL_TEXTURE_2D);
Gl.Begin(Gl.GL_QUADS);
Gl.VertexAttrib2(vert, x, y);
Gl.VertexAttrib2(tvert, ix / image.Width, iy / image.Height);
Gl.VertexAttrib2(vert, x, y + h);
Gl.VertexAttrib2(tvert, ix / image.Width, (iy + ih) / image.Height);
Gl.VertexAttrib2(vert, x + w, y + h);
Gl.VertexAttrib2(tvert, (ix + iw) / image.Width, (iy + ih) / image.Height);
Gl.VertexAttrib2(vert, x + w, y);
Gl.VertexAttrib2(tvert, (ix + iw) / image.Width, iy / image.Height);
Gl.End();
Gl.Disable(Gl.GL_TEXTURE_2D);
Gl.BindTexture(Gl.GL_TEXTURE_2D, 0);
Gl.UseProgram(0);
Gl.Flush();
}