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Request for OpenGL Assistance


maxpowa

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Hello fellow modders, my name is maxpowa and you may be familiar with the mods that I work on; TukMC and more recently, AdvancedHUD. I'm having issues drawing the outline of a rectangle, rather than filling it completely. I think, but I'm not sure if the issue is simply me failing to understand OpenGL and the Minecraft Tessellator.

 

What I currently have, which is failing to draw an unfilled rectangle:

    private static void drawOutlineRect(int x, int y, int x1, int y1, int color)
    {
        GL11.glPushMatrix();
        float f = (float)(color >> 24 & 255) / 255.0F;
        float f1 = (float)(color >> 16 & 255) / 255.0F;
        float f2 = (float)(color >> 8 & 255) / 255.0F;
        float f3 = (float)(color & 255) / 255.0F;
        Tessellator tessellator = Tessellator.instance;
        GL11.glEnable(GL11.GL_BLEND);
        GL11.glDisable(GL11.GL_TEXTURE_2D);
        GL11.glBlendFunc(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA);
        GL11.glColor4f(f1, f2, f3, f);
        
        tessellator.startDrawing(GL11.GL_LINES);

        tessellator.addVertex((double)x, (double)y, 0.0D);   
        tessellator.addVertex((double)x1, (double)y, 0.0D);              
        tessellator.addVertex((double)x1, (double)y1, 0.0D);             
        tessellator.addVertex((double)x, (double)y1, 0.0D);
        tessellator.addVertex((double)x, (double)y, 0.0D);  

        tessellator.draw();

        GL11.glEnable(GL11.GL_TEXTURE_2D);
        GL11.glDisable(GL11.GL_BLEND);
        GL11.glPopMatrix();
    }

 

Thanks in advance,

maxpowa

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So I changed it to not use the tessellator. Still doesn't work.

 

    private static void drawOutlineRect(int x, int y, int x1, int y1, int color)
    {
        GL11.glPushMatrix();
        float f = (float)(color >> 24 & 255) / 255.0F;
        float f1 = (float)(color >> 16 & 255) / 255.0F;
        float f2 = (float)(color >> 8 & 255) / 255.0F;
        float f3 = (float)(color & 255) / 255.0F;
        GL11.glEnable(GL11.GL_BLEND);
        GL11.glDisable(GL11.GL_TEXTURE_2D);
        GL11.glBlendFunc(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA);
        GL11.glColor4f(f1, f2, f3, f);
        
        GL11.glBegin(GL11.GL_LINES);

        GL11.glVertex2d((double)x, (double)y);   
        GL11.glVertex2d((double)x1, (double)y);              
        GL11.glVertex2d((double)x1, (double)y1);             
        GL11.glVertex2d((double)x, (double)y1);
        GL11.glVertex2d((double)x, (double)y);  

        GL11.glEnd();

        GL11.glEnable(GL11.GL_TEXTURE_2D);
        GL11.glDisable(GL11.GL_BLEND);
        GL11.glPopMatrix();
    }

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yeah btw... the tessellator calls opengl function for you. using the tessellator is using opengl...

whats happening when you draw this code? can you send a picture?

how to debug 101:http://www.minecraftforge.net/wiki/Debug_101

-hydroflame, author of the forge revolution-

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could you not just call drawVerticalLine(x, y1, y2, color) and drawHorizontalLine(x1, y, x2, color) to draw each edge individually? seems a lot more simple to me...

 

    private static void drawOutlineRect(int x, int y, int x1, int y1, int color)
    {
        this.drawHorizontalLine(x, y, x1, color);
        this.drawHorizontalLine(x, y1 ,x1,color);
        this.drawVerticalLine(x, y, y1, color);
        this.drawVerticalLine(x1, y, y1, color);
    }

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