[1.5.2] Transparency in GUI [SOLVED]

Hello,

I'm trying to draw a translucent rectangle with Gui.drawRect(); But I did not get :-(

What am I doing wrong?

[spoiler=Code]

@ForgeSubscribe(priority = EventPriority.NORMAL)
public void renderDebugMonitor(RenderGameOverlayEvent event)
{
    ScaledResolution res = new ScaledResolution(this.mc.gameSettings, this.mc.displayWidth, this.mc.displayHeight);

    posX = res.getScaledWidth() - spaceRigth;

    // Draw background
    // posX, posY, descSpace, spaceRight and fontRender is global staic varibles
    int x1 = posX - descSpace - 5;
    int y1 = posY + 8 * (this.fontRender.FONT_HEIGHT + 2) + 5;
    int x2 = posX + 5;
    int y2 = posY - 5;
    Color color = new Color(85, 75, 59, 140); // Alfa is 140, but a rectangle is not translucent

    drawRect(x1, y1, x2, y2, color.getRGB());
}

[spoiler=Screenshot]

Sorry for my bad English, it's not my first language.

Hi

Try

        GL11.glEnable(GL11.GL_BLEND);

at the start of your method.  This turns on the alpha blending function.

-TGG

PS your English is fine, I understood you no problem :-)

Thanks for the advice, but method darwRect() contains this.

[spoiler=Gui.drawRect()]

/**
* Draws a solid color rectangle with the specified coordinates and color. Args: x1, y1, x2, y2, color
*/
public static void drawRect(int par0, int par1, int par2, int par3, int par4)
{
    int j1;

    if (par0 < par2)
    {
        j1 = par0;
        par0 = par2;
        par2 = j1;
    }

    if (par1 < par3)
    {
        j1 = par1;
        par1 = par3;
        par3 = j1;
    }

    float f = (float)(par4 >> 24 & 255) / 255.0F;
    float f1 = (float)(par4 >> 16 & 255) / 255.0F;
    float f2 = (float)(par4 >> 8 & 255) / 255.0F;
    float f3 = (float)(par4 & 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.startDrawingQuads();
    tessellator.addVertex((double)par0, (double)par3, 0.0D);
    tessellator.addVertex((double)par2, (double)par3, 0.0D);
    tessellator.addVertex((double)par2, (double)par1, 0.0D);
    tessellator.addVertex((double)par0, (double)par1, 0.0D);
    tessellator.draw();
    GL11.glEnable(GL11.GL_TEXTURE_2D);
    GL11.glDisable(GL11.GL_BLEND);
}

hmmm yeah you're right

I'm out of ideas then, sorry! :-|

-TGG

Oh... it's a pity :sad:... Thanks for trying to help

P.S. I tried to write the method drawRect without tessellator. When I add the last line GL11.glLoadIdentity(); rectangle becomes transparent, but a new problem arises. All included as a standard GUI becomes invisible. Without this line, rectangle, still not transparent.

[spoiler=Code]

/**
* Draws a solid color rectangle with the specified coordinates and color. Args: x1, y1, x2, y2, color
*/
public static void drawRect(int par0, int par1, int par2, int par3, int par4)
{
    int j1;

    if (par0 < par2)
    {
        j1 = par0;
        par0 = par2;
        par2 = j1;
    }

    if (par1 < par3)
    {
        j1 = par1;
        par1 = par3;
        par3 = j1;
    }

    float f = (float)(par4 >> 24 & 255) / 255.0F;
    float f1 = (float)(par4 >> 16 & 255) / 255.0F;
    float f2 = (float)(par4 >> 8 & 255) / 255.0F;
    float f3 = (float)(par4 & 255) / 255.0F;

    GL11.glEnable(GL11.GL_BLEND);
    GL11.glBlendFunc(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA);
    GL11.glColor4f(f1, f2, f3, f);
    GL11.glBegin(GL11.GL_QUADS);
    GL11.glVertex2f((float) par0, (float) par3);
    GL11.glVertex2f((float) par2, (float) par3);
    GL11.glVertex2f((float) par2, (float) par1);
    GL11.glVertex2f((float) par0, (float) par1);
    GL11.glEnd();
    GL11.glDisable(GL11.GL_BLEND);
    // ** THE MAGIC BEGINS **
    GL11.glLoadIdentity();
    // ** MAGIC ENDS ***
}

[spoiler=Screenshot]

I almost do not know how to use LWJGL. Help please.

Hi

That suggests to me that the reason your transparent rectangle is not transparent is because another part of the GUI is drawing over the top of your transparent rectangle.  GL11.glLoadIdentity might be making it render somewhere offscreen.

Instead of    GL11.glLoadIdentity(), you could try a GL11.glTranslatef or GL11.glScalef to see whether you get both your alpha rectangle and something else on the screen too.  Might be a useful clue.

-TGG

This is code I've used, mostly borrowed from Draco and slightly modified, with drawTexturedModalRect (not the method you're using, I realize) that works for getting transparency:

GL11.glEnable(GL11.GL_BLEND);
GL11.glDisable(GL11.GL_DEPTH_TEST);
GL11.glDepthMask(false);
GL11.glBlendFunc(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA);
GL11.glColor4f(1.0F, 1.0F, 1.0F, 1.0F);
GL11.glDisable(GL11.GL_ALPHA_TEST);
drawTexturedModalRect(xPos, yPos, 0, 0, 56, 9);

Be sure you re-enable or disable whatever you disabled/enabled when you're finished. I don't know much about openGL, so there is probably a better / more efficient way of doing it, and it again it isn't the method you're looking for but maybe you can use drawTexturedModalRect instead. Good luck!

@TheGreyGhost Thanks a lot. I wrote GL11.glTranslatef(0.0f, 0.0f,-1.0f), and that helped. But I'm not quite sure what it is the right decision. Is not it bad form?

@coolAlias Thanks for the advice. I've tried it, but it did not help.

P.S. I like it :3

[spoiler=Screenshot]

Hi

keen, that's a useful clue.

The effect of GL11.glTranslate(0.0f, 0.0f, -1.0f) shows that there is almost certainly another part of the code which is drawing an opaque rectangle over the top of your alpha rectangle.

So ideally it would be best to go find that and turn it off, rather than "fix" it with the translate.

Perhaps you could trace through step by step with a debugger to see if another rect is drawn over the top of yours.  Or alternatively you could look through the I don't have forge on this pc, perhaps there is an obvious method like "drawBackground" or something.

Also - perhaps you need to "cancel" the event before returning from it, to stop the vanilla code from drawing the normal gui screen?

-TGG

The problem is you are using the event wrong.

RenderGameOverlayEvent is a parent event, with a *-load of children.

You need to specify at which step of the event you do the rendering (Pre, or Post ?), and which child event (ElementType) to use. Without that, you are doing the rendering multiple times in the same rendering cycle.

Which basically mean you are rendering your own gui on top of itself.

Hi,

Thanks a lot for help!