add loading texture functions and tweak sdl init

1 files changed, 37 insertions, 1 deletions

diff --git a/sdl/gltools.c b/sdl/gltools.c
index afb0777..2449cfc 100644
--- a/sdl/gltools.c
+++ b/sdl/gltools.c
@@ -11,6 +11,42 @@
 #include <string.h>
 #include "gltools.h"
 
+/* mipmapping enabled by default */
+GLuint gltLoadTGATexture(const char *fname)
+{
+    GLuint handle;
+
+    /* variables used for texture loading */
+    GLbyte *pBytes;
+    GLint iWidth, iHeight, iComponents;
+    GLenum eFormat;
+
+    glGenTextures(1, &handle);
+    glBindTexture(GL_TEXTURE_2D, handle);
+
+    /* load texture */
+    glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, GL_TRUE);
+    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+
+    pBytes = gltLoadTGA(fname, &iWidth, &iHeight, &iComponents, &eFormat);
+    if (!pBytes)
+        fprintf(stderr, "gltLoadTGA: failed to load texture!\n");
+
+    glTexImage2D(GL_TEXTURE_2D, 0, iComponents, iWidth, iHeight, 0, eFormat,
+                 GL_UNSIGNED_BYTE, pBytes);
+    free(pBytes);
+
+    /* seems like mipmapping only applies to MIN_FILTER since mipmapping divides
+     * current texture into smaller and smaller pieces
+     */
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR); /* GL_LINEAR to disable mipmapping */
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+    return handle;
+}
+
 void gltListExtensions(void)
 {
     const GLubyte *ext_str;
@@ -145,7 +181,7 @@ GLint gltWriteTGA(const char *szFileName)
     return 1;
 }
 
-GLbyte *gltLoadTGA(const char *szFileName, GLint *iWidth, GLint *iHeight, 
+GLbyte *gltLoadTGA(const char *szFileName, GLint *iWidth, GLint *iHeight,
                    GLint *iComponents, GLenum *eFormat)
 {
     FILE *pFile;              /* file pointer */