OpenGL尝试绘制多个2d纹理，仅出现第一个 [英] OpenGL trying to Draw Multiple 2d Textures, only 1st one appears

问题描述

我遇到了一个问题，就是我试图使用纹理(每个星球一个纹理)绘制一个太阳系，并且在绘制纹理时，只有第一个出现.其余的都不做.

I've got a problem in that I'm trying to draw a solar system using textures (one texture for each planet) and as I draw my textures, only the 1st one appears. None of the rest do.

我的init函数遍历文件，将纹理保存到对象中，然后遍历对象.在进行迭代时，它会生成纹理并将其使用OpenGL调用绑定到名称.

My init function iterates through my files, saves the textures into an object, and then iterates through the objects. As it's iterating, it generates the textures and binds them to a name using the OpenGL calls.

        SharpGL.OpenGL gl = args.OpenGL;
        gl.Enable(SharpGL.OpenGL.GL_BLEND);
        gl.Enable(SharpGL.OpenGL.GL_TEXTURE_2D);
        gl.BlendFunc(SharpGL.Enumerations.BlendingSourceFactor.SourceAlpha, SharpGL.Enumerations.BlendingDestinationFactor.OneMinusSourceAlpha);                        
        gl.ClearColor(0, 0, 0, 1);

        foreach (ImageWrapper iw in m_images)
        {                            
            uint[] texNames = new uint[1];

            gl.GenTextures(1, texNames);
            gl.BindTexture(SharpGL.OpenGL.GL_TEXTURE_2D, texNames[0]);

            gl.TexParameter(SharpGL.OpenGL.GL_TEXTURE_2D, SharpGL.OpenGL.GL_TEXTURE_WRAP_S, SharpGL.OpenGL.GL_REPEAT);
            gl.TexParameter(SharpGL.OpenGL.GL_TEXTURE_2D, SharpGL.OpenGL.GL_TEXTURE_WRAP_T, SharpGL.OpenGL.GL_REPEAT);
            gl.TexParameter(SharpGL.OpenGL.GL_TEXTURE_2D, SharpGL.OpenGL.GL_TEXTURE_MAG_FILTER, SharpGL.OpenGL.GL_LINEAR);
            gl.TexParameter(SharpGL.OpenGL.GL_TEXTURE_2D, SharpGL.OpenGL.GL_TEXTURE_MIN_FILTER, SharpGL.OpenGL.GL_LINEAR);

            gl.TexImage2D(SharpGL.OpenGL.GL_TEXTURE_2D,
                          0,
                          3,
                          iw.BitmapSource.PixelWidth,
                          iw.BitmapSource.PixelHeight,
                          0,
                          SharpGL.OpenGL.GL_BGRA,
                          SharpGL.OpenGL.GL_UNSIGNED_BYTE,
                          iw.Pixels);

            iw.TextureHandle = texNames;

        }

这是我绘制所有内容的函数.我遍历所有具有纹理数据的对象，并尝试一次绘制一个.我还想执行一些旋转和变换以使我的太阳系旋转.该部分对于出现的纹理效果很好.

Here is my function that draws everything. I iterate through all my objects that have the texture data and try to draw them one at a time. I also want to execute some rotations and transformations to get my solar system to spin. That part works fine for the texture that appears.

        SharpGL.OpenGL gl = args.OpenGL;
        gl.Clear(SharpGL.OpenGL.GL_COLOR_BUFFER_BIT | SharpGL.OpenGL.GL_DEPTH_BUFFER_BIT );
        gl.LoadIdentity();

        float[] data = new float[4];
        foreach (ImageWrapper iw in m_images)
        {
            //gl.MatrixMode(SharpGL.Enumerations.MatrixMode.Modelview);                

            gl.Ortho2D(0, this.Width, 0, this.Height);                
            gl.Enable(OpenGL.GL_TEXTURE_2D);                
            gl.BindTexture(OpenGL.GL_TEXTURE_2D, iw.TextureHandle[0]);
            gl.TexParameter(SharpGL.OpenGL.GL_TEXTURE_2D, SharpGL.OpenGL.GL_TEXTURE_WRAP_S, SharpGL.OpenGL.GL_REPEAT);
            gl.TexParameter(SharpGL.OpenGL.GL_TEXTURE_2D, SharpGL.OpenGL.GL_TEXTURE_WRAP_T, SharpGL.OpenGL.GL_REPEAT);
            gl.TexParameter(SharpGL.OpenGL.GL_TEXTURE_2D, SharpGL.OpenGL.GL_TEXTURE_MAG_FILTER, SharpGL.OpenGL.GL_LINEAR);
            gl.TexParameter(SharpGL.OpenGL.GL_TEXTURE_2D, SharpGL.OpenGL.GL_TEXTURE_MIN_FILTER, SharpGL.OpenGL.GL_LINEAR);


            gl.PushMatrix();
            //gl.Translate(this.Width / 2, this.Height / 2, 0);               

            //gl.Rotate(iw.RotationAboutSun, 0, 0, 1);
            //gl.Translate(iw.X + 1 * this.Width / 2, iw.Y + 1 * this.Height / 2, 0);
            gl.Translate(32,32, 0);
            //gl.Rotate(iw.RotationAboutAxis, 0, 0, 1);  
            //

            gl.Begin(SharpGL.Enumerations.BeginMode.Quads);
            gl.Color(new float[] { 1f,1f,1f});                                          
            gl.TexCoord(0,0);
            gl.Vertex(new double[] { 0 - iw.PixelWidth / 2, 0 - iw.PixelHeight / 2});                
            gl.TexCoord(0,1);
            gl.Vertex(new double[] { 32 - iw.PixelWidth / 2, 0 - iw.PixelHeight / 2 });               
            gl.TexCoord(1,1);
            gl.Vertex(new double[] { 32 - iw.PixelWidth / 2, 32 - iw.PixelHeight / 2 });
            gl.TexCoord(1,0);
            gl.Vertex(new double[] { 0 - iw.PixelWidth / 2, 32 - iw.PixelHeight / 2 });                            
            gl.End();

            gl.PopMatrix();

            gl.Disable(OpenGL.GL_TEXTURE_2D);                

        }

我正在使用C#中的SharpGL库来做到这一点.

I'm using the SharpGL library in C# to do this.

推荐答案

gluOrtho2D()不会像您期望的那样发布glLoadIdentity().

gluOrtho2D() doesn't issue a glLoadIdentity() like you seem to expect.

通常，您仅每帧设置一次投影矩阵 .

Generally you only set your projection matrix once per frame.

尝试这样的事情:

void DrawFrame()
{
    ...

    glMatrixMode( GL_PROJECTION );
    glLoadIdentity();
    gluOrtho2D(0, this.Width, 0, this.Height);

    glMatrixMode( GL_MODELVIEW );
    glLoadIdentity();
    // "camera" transform(s)

    foreach object
    {
        glPushMatrix();
        // per-object matrix transform(s)

        // draw object

        glPopMatrix();
    }
}

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