    001    package net.minecraft.client.renderer;
    002
    003    import cpw.mods.fml.relauncher.Side;
    004    import cpw.mods.fml.relauncher.SideOnly;
    005    import org.lwjgl.opengl.ARBMultitexture;
    006    import org.lwjgl.opengl.GL13;
    007    import org.lwjgl.opengl.GLContext;
    008
    009    @SideOnly(Side.CLIENT)
    010    public class OpenGlHelper
    011    {
    012        /**
    013         * An OpenGL constant corresponding to GL_TEXTURE0, used when setting data pertaining to auxiliary OpenGL texture
    014         * units.
    015         */
    016        public static int defaultTexUnit;
    017
    018        /**
    019         * An OpenGL constant corresponding to GL_TEXTURE1, used when setting data pertaining to auxiliary OpenGL texture
    020         * units.
    021         */
    022        public static int lightmapTexUnit;
    023
    024        /**
    025         * True if the renderer supports multitextures and the OpenGL version != 1.3
    026         */
    027        private static boolean useMultitextureARB = false;
    028
    029        /**
    030         * Initializes the texture constants to be used when rendering lightmap values
    031         */
    032        public static void initializeTextures()
    033        {
    034            useMultitextureARB = GLContext.getCapabilities().GL_ARB_multitexture && !GLContext.getCapabilities().OpenGL13;
    035
    036            if (useMultitextureARB)
    037            {
    038                defaultTexUnit = 33984;
    039                lightmapTexUnit = 33985;
    040            }
    041            else
    042            {
    043                defaultTexUnit = 33984;
    044                lightmapTexUnit = 33985;
    045            }
    046        }
    047
    048        /**
    049         * Sets the current lightmap texture to the specified OpenGL constant
    050         */
    051        public static void setActiveTexture(int par0)
    052        {
    053            if (useMultitextureARB)
    054            {
    055                ARBMultitexture.glActiveTextureARB(par0);
    056            }
    057            else
    058            {
    059                GL13.glActiveTexture(par0);
    060            }
    061        }
    062
    063        /**
    064         * Sets the current lightmap texture to the specified OpenGL constant
    065         */
    066        public static void setClientActiveTexture(int par0)
    067        {
    068            if (useMultitextureARB)
    069            {
    070                ARBMultitexture.glClientActiveTextureARB(par0);
    071            }
    072            else
    073            {
    074                GL13.glClientActiveTexture(par0);
    075            }
    076        }
    077
    078        /**
    079         * Sets the current coordinates of the given lightmap texture
    080         */
    081        public static void setLightmapTextureCoords(int par0, float par1, float par2)
    082        {
    083            if (useMultitextureARB)
    084            {
    085                ARBMultitexture.glMultiTexCoord2fARB(par0, par1, par2);
    086            }
    087            else
    088            {
    089                GL13.glMultiTexCoord2f(par0, par1, par2);
    090            }
    091        }
    092    }