Parse diffuse texture from material

1 files changed, 90 insertions, 13 deletions

diff --git a/tools/ase/main.c b/tools/ase/main.c
index 6ba770a..30c6812 100644
--- a/tools/ase/main.c
+++ b/tools/ase/main.c
@@ -2,12 +2,33 @@
 
 #include <assert.h>
 #include <errno.h>
-#include <stdbool.h>
+#include <linux/limits.h>
 #include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
+void GetParentDir(const char* path, char parent[PATH_MAX]) {
+  assert(path);
+  assert(parent);
+  const size_t path_len = strlen(path);
+  size_t parent_len = path_len - 1;
+  for (; parent_len > 0; --parent_len) {
+    if (path[parent_len] == '/') {
+      break;
+    }
+  }
+  memset(parent, 0, PATH_MAX);
+  memcpy(parent, path, parent_len);
+}
+
+void PathConcat(const char* left, const char* right, char out[PATH_MAX]) {
+  assert(left);
+  assert(right);
+  assert(out);
+  snprintf(out, PATH_MAX, "%s/%s", left, right);
+}
+
 typedef struct Lexeme {
   const char* str;
   size_t      length;
@@ -25,6 +46,8 @@ static void LexerMake(const char* data, size_t size, Lexer* lexer) {
   assert(lexer);
   lexer->buffer = data;
   lexer->size   = size;
+  lexer->next   = 0;
+  lexer->lexeme = (Lexeme){0};
 }
 
 static bool End(const Lexer* lexer) {
@@ -110,6 +133,21 @@ static bool NextLexeme(Lexer* lexer) {
   return lexer->lexeme.length > 0;
 }
 
+static bool ReadLine(Lexer* lexer) {
+  assert(lexer);
+  SkipWhiteSpace(lexer);
+  // Advance until we find a newline character.
+  lexer->lexeme.str = NextPtr(lexer);
+  lexer->lexeme.length = 0;
+  while (HasNext(lexer) && (Next(lexer) != '\n')) {
+    Advance(lexer);
+    lexer->lexeme.length++;
+  }
+  // Skip the newline character.
+  SkipChar(lexer);
+  return lexer->lexeme.length > 0;
+}
+
 static bool ParseFloat(const Lexeme* lex, float* out) {
   assert(lex);
   assert(out);
@@ -136,19 +174,29 @@ typedef struct ModelData {
   uint32_t numPositions;
   uint32_t numNormals;
   uint32_t numTexcoords;
+  Material material;
+  char     mtl_file [PATH_MAX];
   mdTri    tris     [MAX_TRIS];
   mdVec3   positions[MAX_VERTS];
   mdVec3   normals  [MAX_VERTS];
   mdVec2   texcoords[MAX_VERTS];
 } ModelData;
 
+#define PRINT(STR)       printf("%s%.*s\n", STR, (int)lexer->lexeme.length, lexer->lexeme.str)
+#define LEX(STR)         IsLexeme(lexer, STR)
+#define NEXT_LEXEME()    { if (!NextLexeme(lexer)) break; else PRINT("~ "); }
+#define NEXT_FLOAT(PTR)  { NEXT_LEXEME(); if (!ParseFloat(&lexer->lexeme, PTR)) break; }
+#define COPY_LEXEME(BUF) snprintf(BUF, sizeof(BUF), "%.*s", (int)lexer->lexeme.length, lexer->lexeme.str);
+#define NEXT_STRING(BUF) { NEXT_LEXEME(); COPY_LEXEME(BUF); }
+#define READ_LINE(BUF)   { if (!ReadLine(lexer)) break; else { PRINT("~ "); COPY_LEXEME(BUF); } }
+
+// TODO: The current implementation does not support objects within the OBJ
+//  file. It assumes one object and one material. Add support for multiple
+//  objects and materials.
+
 static bool ParseObj(Lexer* lexer, ModelData* modelData) {
   assert(lexer);
   assert(modelData);
-  #define PRINT(STR)      printf("%s%.*s\n", STR, (int)lexer->lexeme.length, lexer->lexeme.str)
-  #define LEX(STR)        IsLexeme(lexer, STR)
-  #define NEXT_LEXEME()   { if (!NextLexeme(lexer)) break; else PRINT("~ "); }
-  #define NEXT_FLOAT(PTR) { NEXT_LEXEME(); if (!ParseFloat(&lexer->lexeme, PTR)) break; }
   bool consumeNext = true;
   for (;;) {
     if (consumeNext) {
@@ -158,7 +206,7 @@ static bool ParseObj(Lexer* lexer, ModelData* modelData) {
     if (LEX("#")) {
       SkipLine(lexer);
     } else if (LEX("mtllib")) {
-      NEXT_LEXEME(); // material file
+      NEXT_STRING(modelData->mtl_file);
       PRINT("> material: ");
     } else if (LEX("o")) {
       NEXT_LEXEME(); // object name
@@ -224,6 +272,21 @@ static bool ParseObj(Lexer* lexer, ModelData* modelData) {
   return true;
 }
 
+static bool ParseMtl(Lexer* lexer, Material* material) {
+  assert(lexer);
+  assert(material);
+  for (;;) {
+    NEXT_LEXEME();
+    if (LEX("newmtl")) {
+      NEXT_LEXEME(); // Material name.
+      PRINT("> material: ");
+    } else if (LEX("map_Kd")) {
+      READ_LINE(material->diffuseTexture);
+    }
+  }
+  return true;
+}
+
 static bool WriteModelFile(const ModelData* modelData, const char* path) {
   assert(modelData);
   assert(path);
@@ -233,8 +296,8 @@ static bool WriteModelFile(const ModelData* modelData, const char* path) {
   Model model  = {0};
   
   // Fill the Model header.
-  IndexedModel* indexed    = &model.indexed;
   model.type               = ModelTypeIndexed;
+  IndexedModel* indexed    = &model.indexed;
   indexed->numTris         = modelData->numTris;
   indexed->numPositions    = modelData->numPositions;
   indexed->numNormals      = modelData->numNormals;
@@ -243,7 +306,8 @@ static bool WriteModelFile(const ModelData* modelData, const char* path) {
   indexed->offsetPositions = indexed->offsetTris      + (modelData->numTris      * sizeof(mdTri));
   indexed->offsetNormals   = indexed->offsetPositions + (modelData->numPositions * sizeof(mdVec3));
   indexed->offsetTexcoords = indexed->offsetNormals   + (modelData->numNormals   * sizeof(mdVec3));
-  
+  memcpy(&model.material, &modelData->material, sizeof(Material));
+
   if ((file = fopen(path, "wb")) == nullptr) {
     fprintf(stderr, "Failed opening output file for writing: %s\n", path);
     goto cleanup;
@@ -299,12 +363,11 @@ static bool ReadFile(const char* path, uint8_t** outData, size_t* outSize) {
   if (fileSize == (size_t)(-1)) {
     goto cleanup;
   }
-  // Allocate one extra byte so that text file data conveniently ends with null.
-  const size_t size = fileSize + 1;
   if (fseek(file, 0, SEEK_SET) != 0) {
     goto cleanup;
   }
-  if ((data = calloc(1, size)) == nullptr) {
+  // Allocate one extra byte so that text file data conveniently ends with null.
+  if ((data = calloc(1, fileSize+1)) == nullptr) {
     goto cleanup;
   }
   if (fread(data, fileSize, 1, file) != 1) {
@@ -312,7 +375,7 @@ static bool ReadFile(const char* path, uint8_t** outData, size_t* outSize) {
   }
   
   *outData = data;
-  *outSize = size;
+  *outSize = fileSize;
   success = true;
   
 cleanup:
@@ -355,10 +418,24 @@ int main(int argc, const char** argv) {
     goto cleanup;
   }
   LexerMake((const char*)fileData, dataSize, &lexer);
-  
   if (!ParseObj(&lexer, modelData)) {
     goto cleanup;
   }
+  if (modelData->mtl_file[0] != 0) {
+    free(fileData);
+    fileData = nullptr;
+    char dir[PATH_MAX];
+    char mtl[PATH_MAX];
+    GetParentDir(filePath, dir);
+    PathConcat(dir, modelData->mtl_file, mtl);
+    if (!ReadFile(mtl, &fileData, &dataSize)) {
+      goto cleanup;
+    }
+    LexerMake((const char*)fileData, dataSize, &lexer);
+    if (!ParseMtl(&lexer, &modelData->material)) {
+      goto cleanup;
+    }
+  }
   if (!WriteModelFile(modelData, outPath)) {
     goto cleanup;
   }