238 lines
6.6 KiB
C++
238 lines
6.6 KiB
C++
#include "Engine.h"
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#include "Sprite.h"
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#include <GL/gl.h>
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#include <GL/glu.h>
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#include <png.h>
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#include <cmath>
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namespace Engine {
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/*
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* Code is taken from http://en.wikibooks.org/wiki/OpenGL_Programming/Intermediate/Textures on
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* Sunday, March 14 2010.
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*/
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bool Sprite::LoadFromPNG (const char *filename) {
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LogDebug ("Loading png from %s", filename);
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//header for testing if it is a png
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png_byte header[8];
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//open file as binary
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FILE *fp = fopen(filename, "rb");
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if (!fp) {
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LogError ("Could not open file: %s", filename);
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return false;
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}
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//read the header
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fread(header, 1, 8, fp);
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//test if png
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int is_png = !png_sig_cmp(header, 0, 8);
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if (!is_png) {
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LogError ("Error opening png file %s: file is not a png file!", filename);
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fclose(fp);
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return false;
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}
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//create png struct
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png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL,
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NULL, NULL);
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if (!png_ptr) {
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LogError ("Error opening png file %s: unable to read png header", filename);
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fclose(fp);
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return (false);
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}
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//create png info struct
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png_infop info_ptr = png_create_info_struct(png_ptr);
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if (!info_ptr) {
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LogError ("Error opening png file %s: unable to read png header", filename);
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png_destroy_read_struct(&png_ptr, (png_infopp) NULL, (png_infopp) NULL);
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fclose(fp);
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return (false);
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}
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//create png info struct
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png_infop end_info = png_create_info_struct(png_ptr);
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if (!end_info) {
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LogError ("Error opening png file %s: unable to read png header", filename);
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png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp) NULL);
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fclose(fp);
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return (false);
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}
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//png error stuff, not sure libpng man suggests this.
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if (setjmp(png_jmpbuf(png_ptr))) {
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LogError ("Error opening png file %s: unable to read png header", filename);
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png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
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fclose(fp);
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return (false);
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}
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//init png reading
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png_init_io(png_ptr, fp);
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//let libpng know you already read the first 8 bytes
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png_set_sig_bytes(png_ptr, 8);
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// read all the info up to the image data
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png_read_info(png_ptr, info_ptr);
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//variables to pass to get info
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int bit_depth, color_type;
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png_uint_32 tmWidth, tmHeight;
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// get info about png
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png_get_IHDR(png_ptr, info_ptr, &tmWidth, &tmHeight, &bit_depth, &color_type,
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NULL, NULL, NULL);
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//update mWidth and mHeight based on png info
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mWidth = tmWidth;
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mHeight = tmHeight;
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// Update the png info struct.
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png_read_update_info(png_ptr, info_ptr);
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// Row size in bytes.
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int rowbytes = png_get_rowbytes(png_ptr, info_ptr);
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// Allocate the image_data as a big block, to be given to opengl
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png_byte *image_data = new png_byte[rowbytes * mHeight];
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if (!image_data) {
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//clean up memory and close stuff
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png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
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fclose(fp);
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return false;
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}
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//row_pointers is for pointing to image_data for reading the png with libpng
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png_bytep *row_pointers = new png_bytep[mHeight];
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if (!row_pointers) {
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//clean up memory and close stuff
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png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
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delete[] image_data;
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fclose(fp);
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return false;
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}
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// set the individual row_pointers to point at the correct offsets of image_data
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for (unsigned int i = 0; i < mHeight; ++i)
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row_pointers[mHeight - 1 - i] = image_data + i * rowbytes;
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//read the png into image_data through row_pointers
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png_read_image(png_ptr, row_pointers);
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//Now generate the OpenGL texture object
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glGenTextures(1, &mGlTextureName);
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glBindTexture(GL_TEXTURE_2D, mGlTextureName);
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glTexImage2D(GL_TEXTURE_2D,0, GL_RGBA, mWidth, mHeight, 0,
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GL_RGBA, GL_UNSIGNED_BYTE, (GLvoid*) image_data);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
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//clean up memory and close stuff
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png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
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delete[] row_pointers;
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delete[] image_data;
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fclose(fp);
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return true;
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}
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void Sprite::DrawAt (float xpos, float ypos, float zpos) {
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float u_start = 0., u_end = 1.;
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if (mAnimation) {
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int frame_index = floor ( (mAnimationFrameRate) * mAnimationTimer);
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u_start = static_cast<float>(frame_index) / mAnimationFrameCount;
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u_end = (frame_index + 1.) / mAnimationFrameCount;
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}
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glPushMatrix();
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glTranslatef (xpos -mScale * mWidth * 0.5, ypos, zpos -mScale * mHeight * 0.5);
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glScalef (mScale, mScale, mScale);
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glDisable(GL_DEPTH_TEST);
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glEnable(GL_TEXTURE_2D);
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glEnable(GL_BLEND);
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glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
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glBindTexture (GL_TEXTURE_2D, mGlTextureName);
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glBegin(GL_QUADS);
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glTexCoord2f (u_start, 0.); glVertex3f (0., 0., 0.);
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glTexCoord2f (u_end, 0.); glVertex3f (0., 0., mHeight);
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glTexCoord2f (u_end, 1.); glVertex3f (mWidth, 0., mHeight);
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glTexCoord2f (u_start, 1.); glVertex3f (mWidth, 0.,0.);
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glEnd();
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glPopMatrix();
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glDisable(GL_TEXTURE_2D);
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glEnable(GL_DEPTH_TEST);
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}
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void Sprite::DrawAt2D (float xpos, float ypos) {
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float u_start = 0., u_end = 1.;
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if (mAnimation) {
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int frame_index = floor ( (mAnimationFrameRate) * mAnimationTimer);
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u_start = static_cast<float>(frame_index) / mAnimationFrameCount;
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u_end = (frame_index + 1.) / mAnimationFrameCount;
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}
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glPushMatrix();
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glTranslatef (xpos -mScale * mWidth * 0.5, ypos, 0.);
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glScalef (mScale, mScale, mScale);
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// \TODO Make 2d drawing of sprites a bit nicer, seems a bit overkill for such a simple function
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glRotatef (-90, 0., 0., 1.);
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glDisable(GL_DEPTH_TEST);
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glEnable(GL_TEXTURE_2D);
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glEnable(GL_BLEND);
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glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
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glBindTexture (GL_TEXTURE_2D, mGlTextureName);
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glBegin(GL_QUADS);
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glTexCoord2f (u_start, 0.); glVertex2f (0., 0.);
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glTexCoord2f (u_end, 0.); glVertex2f (0., mHeight);
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glTexCoord2f (u_end, 1.); glVertex2f (mWidth, mHeight);
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glTexCoord2f (u_start, 1.); glVertex2f (mWidth,0.);
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glEnd();
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glPopMatrix();
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glDisable(GL_TEXTURE_2D);
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glEnable(GL_DEPTH_TEST);
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}
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void Sprite::DrawSubAt (unsigned int index, float xpos, float ypos, float zpos) {
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assert (index < mSubSpriteCount);
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float u_start = static_cast<float>(index) / mSubSpriteCount;
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float u_end = (index + 1.) / mSubSpriteCount;
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glPushMatrix();
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glTranslatef (xpos -mScale * mWidth * 0.5, ypos, zpos -mScale * mHeight * 0.5);
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glScalef (mScale, mScale, mScale);
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glDisable(GL_DEPTH_TEST);
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glEnable(GL_TEXTURE_2D);
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glEnable(GL_BLEND);
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glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
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glBindTexture (GL_TEXTURE_2D, mGlTextureName);
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glBegin(GL_QUADS);
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glTexCoord2f (u_start, 0.); glVertex3f (0., 0., 0.);
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glTexCoord2f (u_end, 0.); glVertex3f (0., 0., mHeight);
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glTexCoord2f (u_end, 1.); glVertex3f (mWidth, 0., mHeight);
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glTexCoord2f (u_start, 1.); glVertex3f (mWidth, 0.,0.);
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glEnd();
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glPopMatrix();
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glDisable(GL_TEXTURE_2D);
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glEnable(GL_DEPTH_TEST);
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}
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}
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