# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1380676177 -10800
# Node ID ef4c9d8eeca7c3d4852f8352d14068aa24edc79c
# Parent  ff3bfd4da86b761a37930a4208c34a0d8205a498
added shaderless distortion method

diff -r ff3bfd4da86b -r ef4c9d8eeca7 oculus1.vcproj
--- a/oculus1.vcproj	Tue Oct 01 12:51:20 2013 +0300
+++ b/oculus1.vcproj	Wed Oct 02 04:09:37 2013 +0300
@@ -553,6 +553,22 @@
 				</File>
 			</Filter>
 		</Filter>
+		<Filter
+			Name="sdr"
+			>
+			<File
+				RelativePath=".\sdr\phong.p.glsl"
+				>
+			</File>
+			<File
+				RelativePath=".\sdr\phong.v.glsl"
+				>
+			</File>
+			<File
+				RelativePath=".\sdr\sdr.glsl"
+				>
+			</File>
+		</Filter>
 	</Files>
 	<Globals>
 	</Globals>
diff -r ff3bfd4da86b -r ef4c9d8eeca7 src/main.cc
--- a/src/main.cc	Tue Oct 01 12:51:20 2013 +0300
+++ b/src/main.cc	Wed Oct 02 04:09:37 2013 +0300
@@ -515,6 +515,13 @@
 	case 'f':
 		toggle_fullscreen();
 		break;
+
+	case '\\':
+		{
+			extern bool dbg_enable;
+			dbg_enable = !dbg_enable;
+		}
+		break;
 	}
 
 	keystate[key] = true;
diff -r ff3bfd4da86b -r ef4c9d8eeca7 src/vr.cc
--- a/src/vr.cc	Tue Oct 01 12:51:20 2013 +0300
+++ b/src/vr.cc	Wed Oct 02 04:09:37 2013 +0300
@@ -10,13 +10,40 @@
 #include <malloc.h>
 #endif
 
+#define USUB	28
+#define VSUB	40
+
+/* these are just used for the shaderless precomputed distortion method */
+struct Mesh {
+	int prim;
+	int num_verts, num_faces;
+	unsigned int vbo;
+	unsigned int ibo;
+};
+struct Vertex {
+	float x, y, z;
+	float tx, ty;
+};
+
+
 static void init_ctx();
 static bool init_ovr();
 static bool init_sdr();
 
+static Mesh gen_view_mesh(int usub, int vsub, float aspect, float lens_center_offset,
+		float scale, const float *dist_factors, float tex_scale_x, float tex_scale_y);
+static void distort_texcoords(float *tc, float aspect, float lens_center_offset, float scale, const float *dist_factors);
+static float barrel_scale(float rad, const float *k);
+
 VRContext vr_ctx;
 static unsigned int sdrprog;
 
+static Mesh wrapmesh[2];
+static bool mesh_valid;
+
+bool dbg_enable;
+
+
 extern "C" int vr_init(enum vr_init_mode mode)
 {
 	glewInit();
@@ -338,49 +365,204 @@
 		{-1, -1, 0, 1},
 		{0, -1, 1, 1}
 	};
+	static const float quad_trans[3] = {0, -1, 1};
+	static const float quad_scale[3] = {1, 0.5, 0.5};
 	static const float offs_scale[3] = {0.0, -1.0, 1.0};
+	static int prev_tex_scale_x, prev_tex_scale_y;
 
 	glPushAttrib(GL_ENABLE_BIT);
 	glDisable(GL_DEPTH_TEST);
 	glDisable(GL_LIGHTING);
-	glEnable(GL_TEXTURE_2D);
+	glDisable(GL_CULL_FACE);
+
+	glMatrixMode(GL_PROJECTION);
+	glPushMatrix();
+	glLoadIdentity();
 
 	glMatrixMode(GL_MODELVIEW);
 	glPushMatrix();
 	glLoadIdentity();
 
-	glMatrixMode(GL_PROJECTION);
-	glPushMatrix();
-	glLoadIdentity();
+	if(!dbg_enable) {
+		glUseProgram(sdrprog);
 
-	glUseProgram(sdrprog);
+		if(sdrprog) {
+			int loc;
+			if((loc = glGetUniformLocation(sdrprog, "lens_center_offset")) != -1) {
+				float offset = vr_ctx.info.lens_center_offset * offs_scale[eye];
+				glUniform1f(loc, offset);
+			}
 
-	if(sdrprog) {
-		int loc;
-		if((loc = glGetUniformLocation(sdrprog, "lens_center_offset")) != -1) {
-			float offset = vr_ctx.info.lens_center_offset * offs_scale[eye];
-			glUniform1f(loc, offset);
+			if((loc = glGetUniformLocation(sdrprog, "tex_scale")) != -1) {
+				glUniform2f(loc, tex_scale_x, tex_scale_y);
+			}
 		}
 
-		if((loc = glGetUniformLocation(sdrprog, "tex_scale")) != -1) {
-			glUniform2f(loc, tex_scale_x, tex_scale_y);
+		glBindTexture(GL_TEXTURE_2D, tex);
+		glBegin(GL_QUADS);
+		glColor4f(1, 1, 1, 1);
+		glTexCoord2f(0, 0); glVertex2f(rects[eye][0], rects[eye][1]);
+		glTexCoord2f(1, 0); glVertex2f(rects[eye][2], rects[eye][1]);
+		glTexCoord2f(1, 1); glVertex2f(rects[eye][2], rects[eye][3]);
+		glTexCoord2f(0, 1); glVertex2f(rects[eye][0], rects[eye][3]);
+		glEnd();
+
+		glUseProgram(0);
+
+	} else {
+
+		if(!mesh_valid || tex_scale_x != prev_tex_scale_x || tex_scale_y != prev_tex_scale_y) {
+			for(int i=0; i<2; i++) {
+				int eye = i + VR_EYE_LEFT;
+
+				if(wrapmesh[i].vbo) {
+					glDeleteBuffers(1, &wrapmesh[i].vbo);
+				}
+				if(wrapmesh[i].ibo) {
+					glDeleteBuffers(1, &wrapmesh[i].ibo);
+				}
+
+				float aspect = vr_ctx.info.aspect / 2.0;
+				float offset = vr_ctx.info.lens_center_offset * offs_scale[eye];
+				wrapmesh[i] = gen_view_mesh(USUB, VSUB, aspect, offset, vr_ctx.info.scale, vr_ctx.info.distort,
+					tex_scale_x, tex_scale_y);
+			}
+			mesh_valid = true;
+			prev_tex_scale_x = tex_scale_x;
+			prev_tex_scale_y = tex_scale_y;
 		}
+
+		glScalef(quad_scale[eye], 1.0, 1.0);
+		glTranslatef(quad_trans[eye], 0, 0);
+
+		glUseProgram(0);
+		glBindTexture(GL_TEXTURE_2D, tex);
+		glEnable(GL_TEXTURE_2D);
+
+		glColor3f(1, 1, 1);
+
+		glEnableClientState(GL_VERTEX_ARRAY);
+		glEnableClientState(GL_TEXTURE_COORD_ARRAY);
+
+		int meshidx = eye - VR_EYE_LEFT;
+		glBindBuffer(GL_ARRAY_BUFFER, wrapmesh[meshidx].vbo);
+		glVertexPointer(3, GL_FLOAT, sizeof(Vertex), 0);
+		glTexCoordPointer(2, GL_FLOAT, sizeof(Vertex), (void*)offsetof(Vertex, tx));
+
+		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, wrapmesh[meshidx].ibo);
+		glDrawElements(GL_TRIANGLES, wrapmesh[meshidx].num_faces * 3, GL_UNSIGNED_INT, 0);
+
+		glBindBuffer(GL_ARRAY_BUFFER, 0);
+		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
+
+		glDisableClientState(GL_VERTEX_ARRAY);
+		glDisableClientState(GL_TEXTURE_COORD_ARRAY);
 	}
 
-	glBindTexture(GL_TEXTURE_2D, tex);
-	glBegin(GL_QUADS);
-	glColor4f(1, 1, 1, 1);
-	glTexCoord2f(0, 0); glVertex2f(rects[eye][0], rects[eye][1]);
-	glTexCoord2f(1, 0); glVertex2f(rects[eye][2], rects[eye][1]);
-	glTexCoord2f(1, 1); glVertex2f(rects[eye][2], rects[eye][3]);
-	glTexCoord2f(0, 1); glVertex2f(rects[eye][0], rects[eye][3]);
-	glEnd();
-
-	glUseProgram(0);
-
+	glMatrixMode(GL_PROJECTION);
 	glPopMatrix();
 	glMatrixMode(GL_MODELVIEW);
 	glPopMatrix();
 
 	glPopAttrib();
 }
+
+static Mesh gen_view_mesh(int usub, int vsub, float aspect, float lens_center_offset,
+		float scale, const float *dist_factors, float tex_scale_x, float tex_scale_y)
+{
+	int uverts = usub + 1;
+	int vverts = vsub + 1;
+
+	int num_verts = uverts * vverts;
+	int num_quads = usub * vsub;
+	int num_tris = num_quads * 2;
+
+	Vertex *varr = new Vertex[num_verts];
+	unsigned int *iarr = new unsigned int[num_tris * 3];
+
+	float du = 1.0 / (float)usub;
+	float dv = 1.0 / (float)vsub;
+
+	Vertex *vptr = varr;
+	for(int i=0; i<vverts; i++) {
+		float v = (float)i * dv;
+		float y = 2.0 * v - 1.0;
+
+		for(int j=0; j<uverts; j++) {
+			float u = (float)j * du;
+			float x = 2.0 * u - 1.0;
+			float tc[2] = {u, v};
+
+			distort_texcoords(tc, aspect, lens_center_offset, scale, dist_factors);
+
+			vptr->x = x;
+			vptr->y = y;
+			vptr->z = 0;
+			vptr->tx = tc[0] * tex_scale_x;
+			vptr->ty = tc[1] * tex_scale_y;
+			vptr++;
+		}
+	}
+
+	unsigned int *iptr = iarr;
+	for(int i=0; i<vsub; i++) {
+		for(int j=0; j<usub; j++) {
+			*iptr++ = i * uverts + j;
+			*iptr++ = (i + 1) * uverts + j;
+			*iptr++ = (i + 1) * uverts + (j + 1);
+
+			*iptr++ = i * uverts + j;
+			*iptr++ = (i + 1) * uverts + (j + 1);
+			*iptr++ = i * uverts + (j + 1);
+		}
+	}
+
+	unsigned int buf[2];
+	glGenBuffers(2, buf);
+	glBindBuffer(GL_ARRAY_BUFFER, buf[0]);
+	glBufferData(GL_ARRAY_BUFFER, num_verts * sizeof *varr, varr, GL_STATIC_DRAW);
+	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buf[1]);
+	glBufferData(GL_ELEMENT_ARRAY_BUFFER, num_tris * 3 * sizeof *iarr, iarr, GL_STATIC_DRAW); 
+
+	delete [] varr;
+	delete [] iarr;
+
+	Mesh mesh;
+	mesh.prim = GL_TRIANGLES;
+	mesh.num_verts = num_verts;
+	mesh.num_faces = num_tris;
+	mesh.vbo = buf[0];
+	mesh.ibo = buf[1];
+	return mesh;
+}
+
+static void distort_texcoords(float *tc, float aspect, float lens_center_offset, float scale, const float *dist_factors)
+{
+	// map tc [0, 1] -> [-1, 1]
+	float ptx = tc[0] * 2.0 - 1.0;
+	float pty = tc[1] * 2.0 - 1.0;
+
+	ptx += lens_center_offset * 2.0;
+	pty /= aspect;	// correct for aspect ratio
+
+	float rad = barrel_scale(ptx * ptx + pty * pty, dist_factors);
+	ptx *= rad;	// scale the point by the computer distortion radius
+	pty *= rad;
+
+	ptx /= scale;
+	pty /= scale;
+
+	pty *= aspect;
+	ptx -= lens_center_offset * 2.0;
+
+	// map back to range [0, 1]
+	tc[0] = ptx * 0.5 + 0.5;
+	tc[1] = pty * 0.5 + 0.5;
+}
+
+static float barrel_scale(float rad, const float *k)
+{
+	float radsq = rad * rad;
+	float radquad = radsq * radsq;
+	return k[0] + k[1] * radsq + k[2] * radquad + k[3] * radquad * radsq;
+}