OpenGL Skybox

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1 comment, last by Zaphyk 8 years, 2 months ago

Hello, I'm trying to create a skybox in OpenGL I managed to draw the cube and change its color but i am not able to bind the texture to the cubemap or to bind the cubemap into the skybox. Below is some of my code in C# (i am using a binding):

The CubeMap class


public class CubeMap
	{
		public uint ID;
		Image Source;
		
		public CubeMap(string source){
			
			Source = new Bitmap(source);
			
			List<Bitmap> Faces = new List<Bitmap>();
			Bitmap NewBmp = new Bitmap(128,128);
			using(Graphics G = Graphics.FromImage(NewBmp)){
				
				G.DrawImage(Source,0,0, new Rectangle(384,128,128,128),GraphicsUnit.Pixel);
				Faces.Add((Bitmap) NewBmp.Clone());//right
				
				G.DrawImage(Source,0,0, new Rectangle(0,128,128,128),GraphicsUnit.Pixel);
				Faces.Add((Bitmap) NewBmp.Clone());//left
				
				G.DrawImage(Source,0,0, new Rectangle(0,0,128,128),GraphicsUnit.Pixel);
				Faces.Add((Bitmap) NewBmp.Clone());//top
				
				G.DrawImage(Source,0,0, new Rectangle(0,256,128,128),GraphicsUnit.Pixel);
				Faces.Add((Bitmap) NewBmp.Clone());
				
				G.DrawImage(Source,0,0, new Rectangle(512,128,128,128),GraphicsUnit.Pixel);
				Faces.Add((Bitmap) NewBmp.Clone());
				
				G.DrawImage(Source,0,0, new Rectangle(128,128,128,128),GraphicsUnit.Pixel);
				Faces.Add((Bitmap) NewBmp.Clone());
			}
			
			GL.GenTextures(1, out ID);
			GL.ActiveTexture(TextureUnit.Texture0);
			GL.BindTexture(TextureTarget.TextureCubeMap, ID);
			
			for(int i = 0; i<Faces.Count; i++){
				System.Drawing.Imaging.BitmapData data = Faces[i].LockBits(new Rectangle(0,0,Faces[i].Width, Faces[i].Height), System.Drawing.Imaging.ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
				
				GL.TexImage2D(TextureTarget.TextureCubeMapPositiveX+i, 0, PixelInternalFormat.Rgb, data.Width, data.Height,0, PixelFormat.Rgb, PixelType.UnsignedByte, data.Scan0);
				
				Faces[i].UnlockBits(data);
			}
			
			GL.TexParameter(TextureTarget.TextureCubeMap, TextureParameterName.TextureMagFilter, (int)TextureMagFilter.Linear);
			GL.TexParameter(TextureTarget.TextureCubeMap, TextureParameterName.TextureMagFilter, (int)TextureMagFilter.Linear);
			GL.TexParameter(TextureTarget.TextureCubeMap, TextureParameterName.TextureWrapS, (int) TextureWrapMode.ClampToEdge);
			GL.TexParameter(TextureTarget.TextureCubeMap, TextureParameterName.TextureWrapT, (int) TextureWrapMode.ClampToEdge);
			GL.TexParameter(TextureTarget.TextureCubeMap, TextureParameterName.TextureWrapR, (int) TextureWrapMode.ClampToEdge);
			
			GL.BindTexture(TextureTarget.TextureCubeMap, 0);
		}

Here I bind the cubemap to the shader


SkyboxShader.Bind();

GL.Uniform1(GL.GetUniformLocation(SkyboxShader.ShaderID, "skybox"), 0);
GL.ActiveTexture(TextureUnit.Texture0);
GL.BindTexture(TextureTarget.TextureCubeMap, Box.ID);//Box is an object of type cubemap 			
GL.BindBuffer(BufferTarget.ArrayBuffer, BufferID);
			
GL.BindVertexArray(ArrayID);
GL.EnableVertexAttribArray(0);
			
GL.DrawArrays(PrimitiveType.Triangles, 0, 36);
			
GL.BindVertexArray(0);
			
SkyboxShader.UnBind();

Vertex Shader


#version 120
attribute vec3 position;
varying vec3 TexCoords;

void main()
{
    gl_Position = vec4(position, 1.0);  
    TexCoords = position;
}

Fragment Shader


#version 120
varying vec3 TexCoords;

uniform samplerCube skybox;

void main()
{   
	gl_FragColor = textureCube(skybox, TexCoords);
}

OpenGL did not throw any errors, and a black box is being rendered instead of the skybox.

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At the start of the code snippet where you are 'binding' your shader, you actually call unbind rather than bind, so that seems a very likely suspect tongue.png. Is this the exact code you are using or is this an error from re-typing your code?

At the start of the code snippet where you are 'binding' your shader, you actually call unbind rather than bind, so that seems a very likely suspect tongue.png. Is this the exact code you are using or is this an error from re-typing your code?

It was a typo from rewriting my code here, I edited the post fixing the typo

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