# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1345512589 -10800
# Node ID 8a0ae6b4aa9b7663d8846fadf2fce8fb3c9f6545
# Parent  5c41e6fcb3009a5fb6c4e24b6b1759c9372dc5ae
trying to make MRT work

diff -r 5c41e6fcb300 -r 8a0ae6b4aa9b prototype/sdr/deferred.p.glsl
--- a/prototype/sdr/deferred.p.glsl	Tue Aug 21 03:17:48 2012 +0300
+++ b/prototype/sdr/deferred.p.glsl	Tue Aug 21 04:29:49 2012 +0300
@@ -1,8 +1,21 @@
-uniform sampler2D mrt0;
+uniform sampler2D mrt0, mrt1, mrt2, mrt3;
 uniform vec2 tex_scale;
 
 void main()
 {
-	vec4 texel0 = texture2D(mrt0, gl_TexCoord[0].st * tex_scale);
-	gl_FragColor = texel0;
+	vec2 tc = gl_TexCoord[0].st;
+	//vec4 texel0 = texture2D(mrt0, gl_TexCoord[0].st * s);
+
+	vec4 texel;
+	if(tc.x < 0.25) {
+		texel = texture2D(mrt0, tc * vec2(4.0, 1.0) * tex_scale);
+	} else if(tc.x < 0.5) {
+		texel = texture2D(mrt0, (tc - vec2(0.25, 0.0)) * vec2(4.0, 1.0) * tex_scale);
+	} else if(tc.x < 0.75) {
+		texel = texture2D(mrt0, (tc - vec2(0.5, 0.0)) * vec2(4.0, 1.0) * tex_scale);
+	} else {
+		texel = texture2D(mrt0, (tc - vec2(0.75, 0.0)) * vec2(4.0, 1.0) * tex_scale);
+	}
+
+	gl_FragColor = texel;
 }
diff -r 5c41e6fcb300 -r 8a0ae6b4aa9b prototype/sdr/mrt.p.glsl
--- a/prototype/sdr/mrt.p.glsl	Tue Aug 21 03:17:48 2012 +0300
+++ b/prototype/sdr/mrt.p.glsl	Tue Aug 21 04:29:49 2012 +0300
@@ -3,5 +3,8 @@
 void main()
 {
 	vec4 texel = texture2D(tex_dif, gl_TexCoord[0].st);
-	gl_FragColor = texel;
+	gl_FragData[0] = texel * vec4(1.0, 0.0, 0.0, 1.0);
+	gl_FragData[1] = texel * vec4(0.0, 1.0, 0.0, 1.0);
+	gl_FragData[2] = texel * vec4(0.0, 0.0, 1.0, 1.0);
+	gl_FragData[3] = texel * vec4(1.0, 0.0, 0.0, 1.0);
 }
diff -r 5c41e6fcb300 -r 8a0ae6b4aa9b prototype/src/renderer.cc
--- a/prototype/src/renderer.cc	Tue Aug 21 03:17:48 2012 +0300
+++ b/prototype/src/renderer.cc	Tue Aug 21 04:29:49 2012 +0300
@@ -14,7 +14,7 @@
 static int round_pow2(int x);
 
 
-#define MRT_COUNT	1
+#define MRT_COUNT	4
 static unsigned int mrt_tex[MRT_COUNT];
 
 static unsigned int mrt_prog;
@@ -37,9 +37,20 @@
 
 bool init_renderer(int xsz, int ysz)
 {
+	int max_draw_buf;
+
+	glGetIntegerv(GL_MAX_DRAW_BUFFERS_ARB, &max_draw_buf);
+	CHECKGLERR;
+	printf("max draw buffers: %d\n", max_draw_buf);
+	if(max_draw_buf < MRT_COUNT) {
+		fprintf(stderr, "OpenGL implementation doesn't support enough draw buffers\n");
+		return false;
+	}
+
 	if(!create_fbo(xsz, ysz)) {
 		return false;
 	}
+	CHECKGLERR;
 
 	if(!(mrt_prog = load_sdr("mrt.v.glsl", "mrt.p.glsl"))) {
 		return false;
@@ -63,8 +74,17 @@
 {
 	int loc;
 
+	static GLenum draw_bufs[] = {
+		GL_COLOR_ATTACHMENT0_EXT, GL_COLOR_ATTACHMENT1_EXT,
+		GL_COLOR_ATTACHMENT2_EXT, GL_COLOR_ATTACHMENT3_EXT,
+		GL_COLOR_ATTACHMENT4_EXT, GL_COLOR_ATTACHMENT5_EXT,
+		GL_COLOR_ATTACHMENT6_EXT, GL_COLOR_ATTACHMENT7_EXT
+	};
+
 	// render into the MRT buffers
 	glBindFramebufferEXT(GL_FRAMEBUFFER, fbo);
+	glDrawBuffersARB(MRT_COUNT, draw_bufs);
+
 	glUseProgram(mrt_prog);
 	draw_func();
 	glUseProgram(0);
@@ -76,12 +96,19 @@
 
 	glDisable(GL_LIGHTING);
 	glDisable(GL_DEPTH_TEST);
-	glBindTexture(GL_TEXTURE_2D, mrt_tex[0]);
-	glEnable(GL_TEXTURE_2D);
 
 	glUseProgram(deferred_debug);
-	if((loc = glGetUniformLocation(deferred_debug, "tex0")) != -1) {
-		glUniform1i(loc, 0);
+	for(int i=0; i<MRT_COUNT; i++) {
+		char uname[32];
+
+		sprintf(uname, "mrt%d", i);
+		if((loc = glGetUniformLocation(deferred_debug, uname)) != -1) {
+			glUniform1i(loc, i);
+		}
+
+		glActiveTexture(GL_TEXTURE0 + i);
+		glBindTexture(GL_TEXTURE_2D, mrt_tex[i]);
+		glEnable(GL_TEXTURE_2D);
 	}
 	if((loc = glGetUniformLocation(deferred_debug, "tex_scale")) != -1) {
 		glUniform2f(loc, (float)fb_xsz / tex_xsz, (float)fb_ysz / tex_ysz);
@@ -98,6 +125,11 @@
 	glVertex2f(-1, 1);
 	glEnd();
 
+	for(int i=0; i<MRT_COUNT; i++) {
+		glActiveTexture(GL_TEXTURE0 + MRT_COUNT - i - 1);
+		glDisable(GL_TEXTURE_2D);
+	}
+
 	glUseProgram(0);
 	glPopAttrib();
 }