loading png textures and reading obj uv coordinates

CMakeLists.txt

@@ -13,6 +13,7 @@ add_executable(${PROJECT_NAME} scripts/main.c
         scripts/light.c
         scripts/texture.c
         scripts/swap.c
+        scripts/upng.c
         scripts/display.c)
 
 # --- SDL2 SETUP ---

assets/cube.obj

@@ -1,46 +1,48 @@
-# Blender v2.76 (sub 0) OBJ File: ''
+
-# www.blender.org
+# cube.obj
+#
+
 mtllib cube.mtl
-o Cube
+o cube
-v 1.000000 -1.000000 -1.000000
+
-v 1.000000 -1.000000 1.000000
 v -1.000000 -1.000000 1.000000
-v -1.000000 -1.000000 -1.000000
+v 1.000000 -1.000000 1.000000
-v 1.000000 1.000000 -0.999999
-v 0.999999 1.000000 1.000001
 v -1.000000 1.000000 1.000000
+v 1.000000 1.000000 1.000000
 v -1.000000 1.000000 -1.000000
-vt 1.000000 0.333333
+v 1.000000 1.000000 -1.000000
-vt 1.000000 0.666667
+v -1.000000 -1.000000 -1.000000
-vt 0.666667 0.666667
+v 1.000000 -1.000000 -1.000000
-vt 0.666667 0.333333
+
-vt 0.666667 0.000000
-vt 0.000000 0.333333
-vt 0.000000 0.000000
-vt 0.333333 0.000000
-vt 0.333333 1.000000
-vt 0.000000 1.000000
-vt 0.000000 0.666667
-vt 0.333333 0.333333
-vt 0.333333 0.666667
 vt 1.000000 0.000000
-vn 0.000000 -1.000000 0.000000
+vt 0.000000 0.000000
+vt 1.000000 1.000000
+vt 0.000000 1.000000
+
+vn 0.000000 0.000000 1.000000
 vn 0.000000 1.000000 0.000000
-vn 1.000000 0.000000 0.000000
-vn -0.000000 0.000000 1.000000
-vn -1.000000 -0.000000 -0.000000
 vn 0.000000 0.000000 -1.000000
-usemtl Material
+vn 0.000000 -1.000000 0.000000
-s off
+vn 1.000000 0.000000 0.000000
-f 2/1/1 3/2/1 4/3/1
+vn -1.000000 0.000000 0.000000
-f 8/1/2 7/4/2 6/5/2
+
-f 5/6/3 6/7/3 2/8/3
+g cube
-f 6/8/4 7/5/4 3/4/4
+usemtl cube
-f 3/9/5 7/10/5 8/11/5
+s 1
-f 1/12/6 4/13/6 8/11/6
+f 1/1/1 2/2/1 3/3/1
-f 1/4/1 2/1/1 4/3/1
+f 3/3/1 2/2/1 4/4/1
-f 5/14/2 8/1/2 6/5/2
+s 2
-f 1/12/3 5/6/3 2/8/3
+f 3/1/2 4/2/2 5/3/2
-f 2/12/4 6/8/4 3/4/4
+f 5/3/2 4/2/2 6/4/2
-f 4/13/5 3/9/5 8/11/5
+s 3
-f 5/6/6 1/12/6 8/11/6
+f 5/4/3 6/3/3 7/2/3
+f 7/2/3 6/3/3 8/1/3
+s 4
+f 7/1/4 8/2/4 1/3/4
+f 1/3/4 8/2/4 2/4/4
+s 5
+f 2/1/5 8/2/5 4/3/5
+f 4/3/5 8/2/5 6/4/5
+s 6
+f 7/1/6 1/2/6 5/3/6
+f 5/3/6 1/2/6 3/4/6

scripts/main.c

@@ -39,7 +39,7 @@ void setup(void) {
     // Creating a SDL texture that is used to display the color buffer
     color_buffer_texture = SDL_CreateTexture(
         renderer,
-        SDL_PIXELFORMAT_ARGB8888,
+        SDL_PIXELFORMAT_RGBA32,
         SDL_TEXTUREACCESS_STREAMING,
         window_width,
         window_height
@@ -53,13 +53,14 @@ void setup(void) {
     proj_matrix = mat4_make_perspective(fov, aspect, znear, zfar);
 
     // Manually load the hardcoded texture data from the static array
-    mesh_texture = (uint32_t*)REDBRICK_TEXTURE;
+    //mesh_texture = (uint32_t*)REDBRICK_TEXTURE;
-    texture_width = 64;
+    //texture_width = 64;
-    texture_height = 64;
+    //texture_height = 64;
+    load_png_texture_data("../assets/cube.png");
 
     // Loads the vertex and face values for the mesh data structure
-    load_cube_mesh_data();
+    //load_cube_mesh_data();
-    // load_obj_file_data("./assets/f22.obj");
+    load_obj_file_data("../assets/cube.obj");
 }
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -131,9 +132,9 @@ void update(void) {
         face_t mesh_face = mesh.faces[i];
 
         vec3_t face_vertices[3];
-        face_vertices[0] = mesh.vertices[mesh_face.a - 1];
+        face_vertices[0] = mesh.vertices[mesh_face.a];
-        face_vertices[1] = mesh.vertices[mesh_face.b - 1];
+        face_vertices[1] = mesh.vertices[mesh_face.b];
-        face_vertices[2] = mesh.vertices[mesh_face.c - 1];
+        face_vertices[2] = mesh.vertices[mesh_face.c];
 
         vec4_t transformed_vertices[3];
 
@@ -316,6 +317,7 @@ void free_resources(void) {
     free(color_buffer);
     array_free(mesh.faces);
     array_free(mesh.vertices);
+    upng_free(png_texture);
 }
 
 ///////////////////////////////////////////////////////////////////////////////

scripts/mesh.c

@@ -24,23 +24,23 @@ vec3_t cube_vertices[N_CUBE_VERTICES] = {
 
 face_t cube_faces[N_CUBE_FACES] = {
     // front
-    { .a = 1, .b = 2, .c = 3, .a_uv = { 0, 0 }, .b_uv = { 0, 1 }, .c_uv = { 1, 1 }, .color = 0xFFFFFFFF },
+    { .a = 1, .b = 2, .c = 3, .a_uv = { 0, 1 }, .b_uv = { 0, 0 }, .c_uv = { 1, 0 }, .color = 0xFFFFFFFF },
-    { .a = 1, .b = 3, .c = 4, .a_uv = { 0, 0 }, .b_uv = { 1, 1 }, .c_uv = { 1, 0 }, .color = 0xFFFFFFFF },
+    { .a = 1, .b = 3, .c = 4, .a_uv = { 0, 1 }, .b_uv = { 1, 0 }, .c_uv = { 1, 1 }, .color = 0xFFFFFFFF },
     // right
-    { .a = 4, .b = 3, .c = 5, .a_uv = { 0, 0 }, .b_uv = { 0, 1 }, .c_uv = { 1, 1 }, .color = 0xFFFFFFFF },
+    { .a = 4, .b = 3, .c = 5, .a_uv = { 0, 1 }, .b_uv = { 0, 0 }, .c_uv = { 1, 0 }, .color = 0xFFFFFFFF },
-    { .a = 4, .b = 5, .c = 6, .a_uv = { 0, 0 }, .b_uv = { 1, 1 }, .c_uv = { 1, 0 }, .color = 0xFFFFFFFF },
+    { .a = 4, .b = 5, .c = 6, .a_uv = { 0, 1 }, .b_uv = { 1, 0 }, .c_uv = { 1, 1 }, .color = 0xFFFFFFFF },
     // back
-    { .a = 6, .b = 5, .c = 7, .a_uv = { 0, 0 }, .b_uv = { 0, 1 }, .c_uv = { 1, 1 }, .color = 0xFFFFFFFF },
+    { .a = 6, .b = 5, .c = 7, .a_uv = { 0, 1 }, .b_uv = { 0, 0 }, .c_uv = { 1, 0 }, .color = 0xFFFFFFFF },
-    { .a = 6, .b = 7, .c = 8, .a_uv = { 0, 0 }, .b_uv = { 1, 1 }, .c_uv = { 1, 0 }, .color = 0xFFFFFFFF },
+    { .a = 6, .b = 7, .c = 8, .a_uv = { 0, 1 }, .b_uv = { 1, 0 }, .c_uv = { 1, 1 }, .color = 0xFFFFFFFF },
     // left
-    { .a = 8, .b = 7, .c = 2, .a_uv = { 0, 0 }, .b_uv = { 0, 1 }, .c_uv = { 1, 1 }, .color = 0xFFFFFFFF },
+    { .a = 8, .b = 7, .c = 2, .a_uv = { 0, 1 }, .b_uv = { 0, 0 }, .c_uv = { 1, 0 }, .color = 0xFFFFFFFF },
-    { .a = 8, .b = 2, .c = 1, .a_uv = { 0, 0 }, .b_uv = { 1, 1 }, .c_uv = { 1, 0 }, .color = 0xFFFFFFFF },
+    { .a = 8, .b = 2, .c = 1, .a_uv = { 0, 1 }, .b_uv = { 1, 0 }, .c_uv = { 1, 1 }, .color = 0xFFFFFFFF },
     // top
-    { .a = 2, .b = 7, .c = 5, .a_uv = { 0, 0 }, .b_uv = { 0, 1 }, .c_uv = { 1, 1 }, .color = 0xFFFFFFFF },
+    { .a = 2, .b = 7, .c = 5, .a_uv = { 0, 1 }, .b_uv = { 0, 0 }, .c_uv = { 1, 0 }, .color = 0xFFFFFFFF },
-    { .a = 2, .b = 5, .c = 3, .a_uv = { 0, 0 }, .b_uv = { 1, 1 }, .c_uv = { 1, 0 }, .color = 0xFFFFFFFF },
+    { .a = 2, .b = 5, .c = 3, .a_uv = { 0, 1 }, .b_uv = { 1, 0 }, .c_uv = { 1, 1 }, .color = 0xFFFFFFFF },
     // bottom
-    { .a = 6, .b = 8, .c = 1, .a_uv = { 0, 0 }, .b_uv = { 0, 1 }, .c_uv = { 1, 1 }, .color = 0xFFFFFFFF },
+    { .a = 6, .b = 8, .c = 1, .a_uv = { 0, 1 }, .b_uv = { 0, 0 }, .c_uv = { 1, 0 }, .color = 0xFFFFFFFF },
-    { .a = 6, .b = 1, .c = 4, .a_uv = { 0, 0 }, .b_uv = { 1, 1 }, .c_uv = { 1, 0 }, .color = 0xFFFFFFFF }
+    { .a = 6, .b = 1, .c = 4, .a_uv = { 0, 1 }, .b_uv = { 1, 0 }, .c_uv = { 1, 1 }, .color = 0xFFFFFFFF }
 };
 
 void load_cube_mesh_data(void) {
@@ -59,6 +59,8 @@ void load_obj_file_data(char* filename) {
     file = fopen(filename, "r");
     char line[1024];
 
+    tex2_t* textcoords = NULL;
+
     while (fgets(line, 1024, file)) {
         // Vertex information
         if (strncmp(line, "v ", 2) == 0) {
@@ -66,6 +68,12 @@ void load_obj_file_data(char* filename) {
             sscanf(line, "v %f %f %f", &vertex.x, &vertex.y, &vertex.z);
             array_push(mesh.vertices, vertex);
         }
+        // texture coordinate information
+        if (strncmp(line, "vt ", 3) == 0) {
+            tex2_t textcoord;
+            sscanf(line, "vt %f %f", &textcoord.u, &textcoord.v);
+            array_push(textcoords, textcoord);
+        }
         // Face information
         if (strncmp(line, "f ", 2) == 0) {
             int vertex_indices[3];
@@ -78,12 +86,16 @@ void load_obj_file_data(char* filename) {
                 &vertex_indices[2], &texture_indices[2], &normal_indices[2]
             ); 
             face_t face = {
-                .a = vertex_indices[0],
+                .a = vertex_indices[0] - 1,
-                .b = vertex_indices[1],
+                .b = vertex_indices[1] - 1,
-                .c = vertex_indices[2],
+                .c = vertex_indices[2] - 1,
+                .a_uv = textcoords[texture_indices[0] - 1],
+                .b_uv = textcoords[texture_indices[1] - 1],
+                .c_uv = textcoords[texture_indices[2] - 1],
                 .color = 0xFFFFFFFF
             };
             array_push(mesh.faces, face);
         }
     }
+    array_free(textcoords);
 }

scripts/texture.c

@@ -4,6 +4,7 @@
 int texture_width = 64;
 int texture_height = 64;
 
+upng_t* png_texture = NULL;
 uint32_t* mesh_texture = NULL;
 
 const uint8_t REDBRICK_TEXTURE[] = {
@@ -72,3 +73,18 @@ const uint8_t REDBRICK_TEXTURE[] = {
     0x38, 0x38, 0x38, 0xff, 0x54, 0x54, 0x54, 0xff, 0x38, 0x38, 0x38, 0xff, 0x54, 0x54, 0x54, 0xff, 0x38, 0x38, 0x38, 0xff, 0x38, 0x38, 0x38, 0xff, 0x38, 0x38, 0x38, 0xff, 0x48, 0x48, 0x48, 0xff, 0x48, 0x48, 0x48, 0xff, 0x48, 0x48, 0x48, 0xff, 0x48, 0x48, 0x48, 0xff, 0x48, 0x48, 0x48, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x38, 0x38, 0x38, 0xff, 0x48, 0x48, 0x48, 0xff, 0x48, 0x48, 0x48, 0xff, 0x48, 0x48, 0x48, 0xff, 0x48, 0x48, 0x48, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x48, 0x48, 0x48, 0xff, 0x48, 0x48, 0x48, 0xff, 0x48, 0x48, 0x48, 0xff, 0x54, 0x54, 0x54, 0xff, 0x48, 0x48, 0x48, 0xff, 0x48, 0x48, 0x48, 0xff, 0x48, 0x48, 0x48, 0xff, 0x54, 0x54, 0x54, 0xff, 0x48, 0x48, 0x48, 0xff, 0x48, 0x48, 0x48, 0xff, 0x38, 0x38, 0x38, 0xff, 0x48, 0x48, 0x48, 0xff, 0x48, 0x48, 0x48, 0xff, 0x48, 0x48, 0x48, 0xff, 0x40, 0x40, 0x40, 0xff, 0x38, 0x38, 0x38, 0xff, 0x38, 0x38, 0x38, 0xff, 0x40, 0x40, 0x40, 0xff, 0x38, 0x38, 0x38, 0xff, 0x38, 0x38, 0x38, 0xff, 0x40, 0x40, 0x40, 0xff, 0x48, 0x48, 0x48, 0xff, 0x40, 0x40, 0x40, 0xff, 0x38, 0x38, 0x38, 0xff, 0x40, 0x40, 0x40, 0xff, 0x54, 0x54, 0x54, 0xff, 0x48, 0x48, 0x48, 0xff, 0x48, 0x48, 0x48, 0xff, 0x38, 0x38, 0x38, 0xff, 0x54, 0x54, 0x54, 0xff, 0x48, 0x48, 0x48, 0xff, 0x48, 0x48, 0x48, 0xff, 0x48, 0x48, 0x48, 0xff, 0x48, 0x48, 0x48, 0xff, 0x40, 0x40, 0x40, 0xff, 0x38, 0x38, 0x38, 0xff, 0x40, 0x40, 0x40, 0xff, 0x48, 0x48, 0x48, 0xff, 0x48, 0x48, 0x48, 0xff, 0x48, 0x48, 0x48, 0xff,
     0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff, 0x54, 0x54, 0x54, 0xff,
 };
+
+void load_png_texture_data(char* filename) {
+    //upng_t * upng;
+
+    png_texture = upng_new_from_file(filename);
+
+    if (png_texture != NULL) {
+        upng_decode(png_texture);
+        if (upng_get_error(png_texture) == UPNG_EOK) {
+            mesh_texture = (uint32_t*)upng_get_buffer(png_texture);
+            texture_height = upng_get_height(png_texture);
+            texture_width = upng_get_width(png_texture);
+        }
+    }
+}

scripts/texture.h

@@ -2,6 +2,7 @@
 #define TEXTURE_H
 
 #include <stdint.h>
+#include "upng.h"
 
 typedef struct {
     float u;
@@ -14,5 +15,8 @@ extern int texture_height;
 extern const uint8_t REDBRICK_TEXTURE[];
 
 extern uint32_t* mesh_texture;
+extern upng_t* png_texture;
+
+void load_png_texture_data(char* filename);
 
 #endif

scripts/triangle.c

@@ -262,6 +262,11 @@ void draw_textured_triangle(
         float_swap(&v0, &v1);
     }
 
+    // flip v component to account for inverted uv coordinates (where v grows downwrds)
+    v0 = 1.0f - v0;
+    v1 = 1.0f - v1;
+    v2 = 1.0f - v2;
+
     // Create vector points and texture coords after we sort the vertices
     vec4_t point_a = { x0, y0, z0, w0 };
     vec4_t point_b = { x1, y1, z1, w1 };

scripts/upng.h

@@ -0,0 +1,81 @@
+/*
+uPNG -- derived from LodePNG version 20100808
+
+Copyright (c) 2005-2010 Lode Vandevenne
+Copyright (c) 2010 Sean Middleditch
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+		1. The origin of this software must not be misrepresented; you must not
+		claim that you wrote the original software. If you use this software
+		in a product, an acknowledgment in the product documentation would be
+		appreciated but is not required.
+
+		2. Altered source versions must be plainly marked as such, and must not be
+		misrepresented as being the original software.
+
+		3. This notice may not be removed or altered from any source
+		distribution.
+*/
+
+#if !defined(UPNG_H)
+#define UPNG_H
+
+typedef enum upng_error {
+	UPNG_EOK			= 0, /* success (no error) */
+	UPNG_ENOMEM			= 1, /* memory allocation failed */
+	UPNG_ENOTFOUND		= 2, /* resource not found (file missing) */
+	UPNG_ENOTPNG		= 3, /* image data does not have a PNG header */
+	UPNG_EMALFORMED		= 4, /* image data is not a valid PNG image */
+	UPNG_EUNSUPPORTED	= 5, /* critical PNG chunk type is not supported */
+	UPNG_EUNINTERLACED	= 6, /* image interlacing is not supported */
+	UPNG_EUNFORMAT		= 7, /* image color format is not supported */
+	UPNG_EPARAM			= 8  /* invalid parameter to method call */
+} upng_error;
+
+typedef enum upng_format {
+	UPNG_BADFORMAT,
+	UPNG_RGB8,
+	UPNG_RGB16,
+	UPNG_RGBA8,
+	UPNG_RGBA16,
+	UPNG_LUMINANCE1,
+	UPNG_LUMINANCE2,
+	UPNG_LUMINANCE4,
+	UPNG_LUMINANCE8,
+	UPNG_LUMINANCE_ALPHA1,
+	UPNG_LUMINANCE_ALPHA2,
+	UPNG_LUMINANCE_ALPHA4,
+	UPNG_LUMINANCE_ALPHA8
+} upng_format;
+
+typedef struct upng_t upng_t;
+
+upng_t*		upng_new_from_bytes	(const unsigned char* buffer, unsigned long size);
+upng_t*		upng_new_from_file	(const char* path);
+void		upng_free			(upng_t* upng);
+
+upng_error	upng_header			(upng_t* upng);
+upng_error	upng_decode			(upng_t* upng);
+
+upng_error	upng_get_error		(const upng_t* upng);
+unsigned	upng_get_error_line	(const upng_t* upng);
+
+unsigned	upng_get_width		(const upng_t* upng);
+unsigned	upng_get_height		(const upng_t* upng);
+unsigned	upng_get_bpp		(const upng_t* upng);
+unsigned	upng_get_bitdepth	(const upng_t* upng);
+unsigned	upng_get_components	(const upng_t* upng);
+unsigned	upng_get_pixelsize	(const upng_t* upng);
+upng_format	upng_get_format		(const upng_t* upng);
+
+const unsigned char*	upng_get_buffer		(const upng_t* upng);
+unsigned				upng_get_size		(const upng_t* upng);
+
+#endif /*defined(UPNG_H)*/