I'm completely new to opengl. I have created a shader code for displaying an image(file1) by replacing it's dark area to red color. It is working with below code. Not sure even this code are written properly. Now I want to show two images (file1,file2) side by side on same openGL with same condition on shader code. For that I have to create multitexturing. How can I achieve it? What changes should made on below code?
public partial class Form7ImageOnly : Form
{
Bitmap FrameData;
bool loaded = false;
string file1 = "penguine.png";
string file2 = "dove.png";
int program;
int vertShader;
int fragShader;
int buffer;
int positionLocation;
int texture;
int ScreenWidth;
int ScreenHeight;
float[] vertices = {
// Left bottom triangle
-1f, -1f, 0f,
1f, -1f, 0f,
1f, 1f, 0f,
// Right top triangle
1f, 1f, 0f,
-1f, 1f, 0f,
-1f, -1f, 0f
};
public Form7ImageOnly()
{
InitializeComponent();
}
private void Form7ImageOnly_Load(object sender, EventArgs e)
{
glControl.Resize += new EventHandler(glControl_Resize);
glControl.Paint += new PaintEventHandler(glControl_Paint);
GL.ClearColor(Color.Yellow);
GL.Enable(EnableCap.DepthTest);
Application.Idle += Application_Idle;
// Ensure that the viewport and projection matrix are set correctly.
glControl_Resize(glControl, EventArgs.Empty);
}
void Application_Idle(object sender, EventArgs e)
{
while (glControl.IsIdle)
{
Render();
}
}
private void Render()
{
ScreenWidth = Screen.PrimaryScreen.Bounds.Width;
ScreenHeight = Screen.PrimaryScreen.Bounds.Height;
glControl.Size = new System.Drawing.Size(ScreenWidth, ScreenHeight);
texture = LoadTexture(file);
GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);
DrawImage(texture);
}
private void glControl_Paint(object sender, PaintEventArgs e)
{
Render();
}
private void glControl_Resize(object sender, EventArgs e)
{
Init();
}
private void Init()
{
CreateShaders();
CreateProgram();
InitBuffers();
}
public void DrawImage(int image)
{
GL.Viewport(new Rectangle(0, 0, ScreenWidth, ScreenHeight));
GL.MatrixMode(MatrixMode.Projection);
GL.PushMatrix();
GL.LoadIdentity();
//GL.Ortho(0, 1920, 0, 1080, 0, 1);
GL.MatrixMode(MatrixMode.Modelview);
GL.PushMatrix();
GL.LoadIdentity();
GL.Disable(EnableCap.Lighting);
GL.Enable(EnableCap.Texture2D);
GL.ActiveTexture(TextureUnit.Texture0);
GL.BindTexture(TextureTarget.Texture2D, image);
//GL.Begin(PrimitiveType.Quads);
//GL.TexCoord2(0, 1);
//GL.Vertex3(0, 0, 0);
//GL.TexCoord2(1, 1);
//GL.Vertex3(1920, 0, 0);
//GL.TexCoord2(1, 0);
//GL.Vertex3(1920, 1080, 0);
//GL.TexCoord2(0, 0);
//GL.Vertex3(0, 1080, 0);
//GL.End();
RunShaders();
GL.Disable(EnableCap.Texture2D);
GL.PopMatrix();
GL.MatrixMode(MatrixMode.Projection);
GL.PopMatrix();
GL.MatrixMode(MatrixMode.Modelview);
ErrorCode ec = GL.GetError();
if (ec != 0)
System.Console.WriteLine(ec.ToString());
Console.Read();
glControl.SwapBuffers();
}
private void RunShaders()
{
GL.ClearColor(Color.Yellow);
GL.UseProgram(program);
GL.DrawArrays(PrimitiveType.Triangles, 0, vertices.Length / 3);
ErrorCode ec = GL.GetError();
if (ec != 0)
System.Console.WriteLine(ec.ToString());
Console.Read();
}
private void CreateProgram()
{
program = GL.CreateProgram();
GL.AttachShader(program, vertShader);
GL.AttachShader(program, fragShader);
GL.LinkProgram(program);
}
private void CreateShaders()
{
/***********Vert Shader********************/
vertShader = GL.CreateShader(ShaderType.VertexShader);
GL.ShaderSource(vertShader, @"attribute vec3 a_position;
varying vec2 vTexCoord;
void main() {
vTexCoord = (a_position.xy + 1) / 2;
gl_Position = vec4(a_position, 1);
}");
GL.CompileShader(vertShader);
/***********Frag Shader ****************/
fragShader = GL.CreateShader(ShaderType.FragmentShader);
GL.ShaderSource(fragShader, @"precision highp float;
uniform sampler2D sTexture;
varying vec2 vTexCoord;
void main ()
{
vec4 color = texture2D (sTexture, vTexCoord);
if(color.r < 0.3){color.r = 1.0;}
// Save the result
gl_FragColor = color;
}");
GL.CompileShader(fragShader);
}
private void InitBuffers()
{
buffer = GL.GenBuffer();
positionLocation = GL.GetAttribLocation(program, "a_position");
GL.EnableVertexAttribArray(positionLocation);
GL.BindBuffer(BufferTarget.ArrayBuffer, buffer);
GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(vertices.Length * sizeof(float)), vertices, BufferUsageHint.StaticDraw);
GL.VertexAttribPointer(positionLocation, 3, VertexAttribPointerType.Float, false, 0, 0);
}
public int LoadTexture(string file)
{
Bitmap bitmap = new Bitmap(file);
int tex = -1;
if (bitmap != null)
{
GL.DeleteTextures(1, ref tex);
GL.Hint(HintTarget.PerspectiveCorrectionHint, HintMode.Nicest);
GL.GenTextures(1, out tex);
GL.BindTexture(TextureTarget.Texture2D, tex);
bitmap.RotateFlip(RotateFlipType.RotateNoneFlipY);
BitmapData data = bitmap.LockBits(new System.Drawing.Rectangle(0, 0, bitmap.Width, bitmap.Height),
ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
GL.TexImage2D(TextureTarget.Texture2D, 0, PixelInternalFormat.Rgba, data.Width, data.Height, 0,
OpenTK.Graphics.OpenGL.PixelFormat.Bgra, PixelType.UnsignedByte, data.Scan0);
bitmap.UnlockBits(data);
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMinFilter, (int)TextureMinFilter.Linear);
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMagFilter, (int)TextureMagFilter.Linear);
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapS, (int)TextureWrapMode.ClampToEdge);
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapT, (int)TextureWrapMode.ClampToEdge);
}
return tex;
}
}
