was stimmt hier dran nicht?
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Hallo,
Ich versuche eine TGA einzulesen und die RGBA Daten zu extrahieren. Ich muss irgendwo einen Fehler machen, denn es funktioniert nicht korrekt. Der Anfang der Ausgabe scheint zwar korrekt zu sein aber danach hängt er immer noch mehr an, z.b. bei einer 30*30 datei generiert er mehr als 900 einträge, wobei die ersten 900 soweit ich es sehe richtig sind
#include <stdio.h> int main(int argc, char* argv[]) { FILE *fp; unsigned char ident_field_size; unsigned char color_map_type; unsigned char image_type; unsigned short x_origin, y_origin; unsigned short width, height; unsigned char bits_per_pixel; unsigned char packet_header; unsigned char rep_count; unsigned char i; int rgba; if( argc < 2 ){ printf("Syntax : tga2c.exe <tga file> <c name>\n"); return 0; } if( (fp = fopen(argv[1], "rb")) == NULL ){ printf("Couldn't open file.\n"); return 1; } fread( &ident_field_size, 1, 1, fp ); fread( &color_map_type, 1, 1, fp ); fread( &image_type, 1, 1, fp ); if( color_map_type != 0 || image_type != 10 ) { printf("Only run-length encoded RGB images supported.\n"); return 1; } // skip color map fseek( fp, 5, SEEK_CUR ); fread( &x_origin, 2, 1, fp ); fread( &y_origin, 2, 1, fp ); fread( &width, 2, 1, fp ); fread( &height, 2, 1, fp ); fread( &bits_per_pixel, 1, 1, fp ); if( bits_per_pixel != 32 ){ printf("bpp=%i\nonly 32bit rgba images supported.\n", bits_per_pixel); return 1; } // skip image descriptor byte fseek( fp, 1, SEEK_CUR ); // skip identification field if( ident_field_size != 0 ) fseek( fp, ident_field_size, SEEK_CUR ); // read image data while(!feof(fp)) { fread( &packet_header, 1, 1, fp ); // run length packet if( packet_header & 128 ){ rep_count = packet_header ^ 128; fread( &rgba, 4, 1, fp ); for( i = 0; i < rep_count+1; i++ ) printf("RGBA : 0x%x // runlength\n", rgba); } else { // raw packet rep_count = packet_header; for( i = 0; i < rep_count+1; i++ ){ fread( &rgba, 4, 1, fp ); printf("RGBA : 0x%x // raw\n", rgba ); } } } fclose(fp); return 0; }Das Datei format kann man sich hier angucken :
-------------------------------------------------------------------------------- DATA TYPE 10: Run Length Encoded, RGB images. | _______________________________________________________________________________| | Offset | Length | Description | |--------|--------|------------------------------------------------------------| |--------|--------|------------------------------------------------------------| | 0 | 1 | Number of Characters in Identification Field. | | | | | | | | This field is a one-byte unsigned integer, specifying | | | | the length of the Image Identification Field. Its range | | | | is 0 to 255. A value of 0 means that no Image | | | | Identification Field is included. | | | | | |--------|--------|------------------------------------------------------------| | 1 | 1 | Color Map Type. | | | | | | | | This field contains either 0 or 1. 0 means no color map | | | | is included. 1 means a color map is included, but since | | | | this is an unmapped image it is usually ignored. TIPS | | | | ( a Targa paint system ) will set the border color | | | | the first map color if it is present. Wowie zowie. | | | | | |--------|--------|------------------------------------------------------------| | 2 | 1 | Image Type Code. | | | | | | | | Binary 10 for this type of image. | | | | | |--------|--------|------------------------------------------------------------| | 3 | 5 | Color Map Specification. | | | | | | | | Ignored if Color Map Type is 0; otherwise, interpreted | | | | as follows: | | | | | | 3 | 2 | Color Map Origin. | | | | Integer ( lo-hi ) index of first color map entry. | | | | | | 5 | 2 | Color Map Length. | | | | Integer ( lo-hi ) count of color map entries. | | | | | | 7 | 1 | Color Map Entry Size. | | | | Number of bits in color map entry. This value is 16 for | | | | the Targa 16, 24 for the Targa 24, 32 for the Targa 32. | | | | | |--------|--------|------------------------------------------------------------| | 8 | 10 | Image Specification. | | | | | | 8 | 2 | X Origin of Image. | | | | Integer ( lo-hi ) X coordinate of the lower left corner | | | | of the image. | | | | | | 10 | 2 | Y Origin of Image. | | | | Integer ( lo-hi ) Y coordinate of the lower left corner | | | | of the image. | | | | | | 12 | 2 | Width of Image. | | | | Integer ( lo-hi ) width of the image in pixels. | | | | | | 14 | 2 | Height of Image. | | | | Integer ( lo-hi ) height of the image in pixels. | | | | | | 16 | 1 | Image Pixel Size. | | | | Number of bits in a pixel. This is 16 for Targa 16, | | | | 24 for Targa 24, and .... well, you get the idea. | | | | | | 17 | 1 | Image Descriptor Byte. | | | | Bits 3-0 - number of attribute bits associated with each | | | | pixel. For the Targa 16, this would be 0 or | | | | 1. For the Targa 24, it should be 0. For the | | | | Targa 32, it should be 8. | | | | Bit 4 - reserved. Must be set to 0. | | | | Bit 5 - screen origin bit. | | | | 0 = Origin in lower left-hand corner. | | | | 1 = Origin in upper left-hand corner. | | | | Must be 0 for Truevision images. | | | | Bits 7-6 - Data storage interleaving flag. | | | | 00 = non-interleaved. | | | | 01 = two-way (even/odd) interleaving. | | | | 10 = four way interleaving. | | | | 11 = reserved. | | | | | |--------|--------|------------------------------------------------------------| | 18 | varies | Image Identification Field. | | | | Contains a free-form identification field of the length | | | | specified in byte 1 of the image record. It's usually | | | | omitted ( length in byte 1 = 0 ), but can be up to 255 | | | | characters. If more identification information is | | | | required, it can be stored after the image data. | | | | | |--------|--------|------------------------------------------------------------| | varies | varies | Color map data. | | | | | | | | If the Color Map Type is 0, this field doesn't exist. | | | | Otherwise, just read past it to get to the image. | | | | The Color Map Specification, describes the size of each | | | | entry, and the number of entries you'll have to skip. | | | | Each color map entry is 2, 3, or 4 bytes. | | | | | |--------|--------|------------------------------------------------------------| | varies | varies | Image Data Field. | | | | | | | | This field specifies (width) x (height) pixels. The | | | | RGB color information for the pixels is stored in | | | | packets. There are two types of packets: Run-length | | | | encoded packets, and raw packets. Both have a 1-byte | | | | header, identifying the type of packet and specifying a | | | | count, followed by a variable-length body. | | | | The high-order bit of the header is "1" for the | | | | run length packet, and "0" for the raw packet. | | | | | | | | For the run-length packet, the header consists of: | | | | __________________________________________________ | | | | | 1 bit | 7 bit repetition count minus 1. | | | | | | ID | Since the maximum value of this | | | | | | | field is 127, the largest possible | | | | | | | run size would be 128. | | | | | |-------|----------------------------------------| | | | | | 1 | C C C C C C C | | | | | -------------------------------------------------- | | | | | | | | For the raw packet, the header consists of: | | | | __________________________________________________ | | | | | 1 bit | 7 bit number of pixels minus 1. | | | | | | ID | Since the maximum value of this | | | | | | | field is 127, there can never be | | | | | | | more than 128 pixels per packet. | | | | | |-------|----------------------------------------| | | | | | 0 | N N N N N N N | | | | | -------------------------------------------------- | | | | | | | | | | | | For the run length packet, the header is followed by | | | | a single color value, which is assumed to be repeated | | | | the number of times specified in the header. The | | | | packet may cross scan lines ( begin on one line and end | | | | on the next ). | | | | | | | | For the raw packet, the header is followed by | | | | the number of color values specified in the header. | | | | | | | | The color entries themselves are two bytes, three bytes, | | | | or four bytes ( for Targa 16, 24, and 32 ), and are | | | | broken down as follows: | | | | | | | | The 2 byte entry - | | | | ARRRRRGG GGGBBBBB, where each letter represents a bit. | | | | But, because of the lo-hi storage order, the first byte | | | | coming from the file will actually be GGGBBBBB, and the | | | | second will be ARRRRRGG. "A" represents an attribute bit. | | | | | | | | The 3 byte entry contains 1 byte each of blue, green, | | | | and red. | | | | | | | | The 4 byte entry contains 1 byte each of blue, green, | | | | red, and attribute. For faster speed (because of the | | | | hardware of the Targa board itself), Targa 24 image are | | | | sometimes stored as Targa 32 images. | | | | | --------------------------------------------------------------------------------
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du brauchst einen debugger
es gibt da etwas namens "printlining", auch http://de.wikipedia.org/wiki/Ablaufverfolgung
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hallo,
hat sich erledigt, aus irgendeinem grund stehen hinter den bild daten noch ein paar bytes, weiss zwar nicht wieso aber wenn an die while(!feof()) schleife ändert und nur genau soviele pixel liest wie das bild gross ist, stimmt alles.