snes9x/gtk/src/shaders/shader_helpers.cpp

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2018-05-10 23:47:55 +00:00
#include <epoxy/gl.h>
#include <png.h>
#include <stdlib.h>
#include <string.h>
#include "shader_helpers.h"
static void gl_error_callback( GLenum source,
GLenum type,
GLuint id,
GLenum severity,
GLsizei length,
const GLchar* message,
const void* userParam )
{
if (type== GL_DEBUG_TYPE_ERROR)
{
fprintf( stderr, "GL: %s type = 0x%x, severity = 0x%x, \n %s\n",
(type == GL_DEBUG_TYPE_ERROR ? "*ERROR*" : ""),
type, severity, message );
}
else
{
fprintf( stderr, "GL type = 0x%x, severity = 0x%x, \n %s\n",
type, severity, message);
}
return;
}
void glLogErrors (void)
{
glEnable (GL_DEBUG_OUTPUT);
glDebugMessageCallback ((GLDEBUGPROC) gl_error_callback, 0);
}
bool loadPngImage(const char* name,
int& outWidth,
int& outHeight,
bool& outHasAlpha,
GLubyte** outData)
{
png_structp png_ptr;
png_infop info_ptr;
unsigned int sig_read = 0;
FILE* fp;
if ((fp = fopen(name, "rb")) == NULL)
return false;
/* Create and initialize the png_struct
* with the desired error handler
* functions. If you want to use the
* default stderr and longjump method,
* you can supply NULL for the last
* three parameters. We also supply the
* the compiler header file version, so
* that we know if the application
* was compiled with a compatible version
* of the library. REQUIRED
*/
png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (png_ptr == NULL) {
fclose(fp);
return false;
}
/* Allocate/initialize the memory
* for image information. REQUIRED. */
info_ptr = png_create_info_struct(png_ptr);
if (info_ptr == NULL) {
fclose(fp);
png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
return false;
}
/* Set error handling if you are
* using the setjmp/longjmp method
* (this is the normal method of
* doing things with libpng).
* REQUIRED unless you set up
* your own error handlers in
* the png_create_read_struct()
* earlier.
*/
if (setjmp(png_jmpbuf(png_ptr))) {
/* Free all of the memory associated
* with the png_ptr and info_ptr */
png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
fclose(fp);
/* If we get here, we had a
* problem reading the file */
return false;
}
/* Set up the output control if
* you are using standard C streams */
png_init_io(png_ptr, fp);
/* If we have already
* read some of the signature */
png_set_sig_bytes(png_ptr, sig_read);
/*
* If you have enough memory to read
* in the entire image at once, and
* you need to specify only
* transforms that can be controlled
* with one of the PNG_TRANSFORM_*
* bits (this presently excludes
* dithering, filling, setting
* background, and doing gamma
* adjustment), then you can read the
* entire image (including pixels)
* into the info structure with this
* call
*
* PNG_TRANSFORM_STRIP_16 |
* PNG_TRANSFORM_PACKING forces 8 bit
* PNG_TRANSFORM_EXPAND forces to
* expand a palette into RGB
*/
png_read_png(png_ptr,
info_ptr,
PNG_TRANSFORM_STRIP_16 | PNG_TRANSFORM_PACKING | PNG_TRANSFORM_EXPAND,
(png_voidp)NULL);
outWidth = png_get_image_width(png_ptr, info_ptr);
outHeight = png_get_image_height(png_ptr, info_ptr);
switch (png_get_color_type(png_ptr, info_ptr)) {
case PNG_COLOR_TYPE_RGBA:
outHasAlpha = true;
break;
case PNG_COLOR_TYPE_RGB:
outHasAlpha = false;
break;
default:
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
fclose(fp);
return false;
}
unsigned int row_bytes = png_get_rowbytes(png_ptr, info_ptr);
*outData = (unsigned char*)malloc(row_bytes * outHeight);
png_bytepp row_pointers = png_get_rows(png_ptr, info_ptr);
for (int i = 0; i < outHeight; i++) {
memcpy(*outData + (row_bytes * i), row_pointers[i], row_bytes);
}
/* Clean up after the read,
* and free any memory allocated */
png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
/* Close the file */
fclose(fp);
/* That's it */
return true;
}
bool loadTGA(const char* filename, STGA& tgaFile)
{
FILE* file;
unsigned char type[4];
unsigned char info[6];
file = fopen(filename, "rb");
if (!file)
return false;
fread(&type, sizeof(char), 3, file);
fseek(file, 12, SEEK_SET);
fread(&info, sizeof(char), 6, file);
// image type either 2 (color) or 3 (greyscale)
if (type[1] != 0 || (type[2] != 2 && type[2] != 3)) {
fclose(file);
return false;
}
tgaFile.width = info[0] + info[1] * 256;
tgaFile.height = info[2] + info[3] * 256;
tgaFile.byteCount = info[4] / 8;
if (tgaFile.byteCount != 3 && tgaFile.byteCount != 4) {
fclose(file);
return false;
}
long imageSize = tgaFile.width * tgaFile.height * tgaFile.byteCount;
// allocate memory for image data
unsigned char* tempBuf = new unsigned char[imageSize];
tgaFile.data = new unsigned char[tgaFile.width * tgaFile.height * 4];
// read in image data
fread(tempBuf, sizeof(unsigned char), imageSize, file);
// swap line order and convert to RBGA
for (int i = 0; i < tgaFile.height; i++) {
unsigned char* source = tempBuf + tgaFile.width * (tgaFile.height - 1 - i) * tgaFile.byteCount;
unsigned char* destination = tgaFile.data + tgaFile.width * i * 4;
for (int j = 0; j < tgaFile.width; j++) {
destination[0] = source[2];
destination[1] = source[1];
destination[2] = source[0];
destination[3] = tgaFile.byteCount == 4 ? source[3] : 0xff;
source += tgaFile.byteCount;
destination += 4;
}
}
delete[] tempBuf;
tgaFile.byteCount = 4;
// close file
fclose(file);
return true;
}