Add a mipmap sample

This commit is contained in:
Luke Benstead 2019-09-23 21:31:11 +01:00
parent 888a48562f
commit aafb99dede
5 changed files with 246 additions and 0 deletions

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@ -28,3 +28,4 @@ all:
$(KOS_MAKE) -C polymark all
$(KOS_MAKE) -C polygon_offset all
$(KOS_MAKE) -C blend_test all
$(KOS_MAKE) -C mipmap all

29
samples/mipmap/Makefile Normal file
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TARGET = mipmap.elf
OBJS = main.o
all: rm-elf $(TARGET)
include $(KOS_BASE)/Makefile.rules
clean:
-rm -f $(TARGET) $(OBJS) romdisk.*
rm-elf:
-rm -f $(TARGET) romdisk.*
$(TARGET): $(OBJS) romdisk.o
$(KOS_CC) $(KOS_CFLAGS) $(KOS_LDFLAGS) -o $(TARGET) $(KOS_START) \
$(OBJS) romdisk.o $(OBJEXTRA) -lm -lkosutils $(KOS_LIBS)
romdisk.img:
$(KOS_GENROMFS) -f romdisk.img -d romdisk -v
romdisk.o: romdisk.img
$(KOS_BASE)/utils/bin2o/bin2o romdisk.img romdisk romdisk.o
run: $(TARGET)
$(KOS_LOADER) $(TARGET)
dist:
rm -f $(OBJS) romdisk.o romdisk.img
$(KOS_STRIP) $(TARGET)

216
samples/mipmap/main.c Normal file
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#include <stdio.h>
#include <stdlib.h>
#include "gl.h"
#include "glu.h"
#include "glkos.h"
extern uint8 romdisk[];
KOS_INIT_ROMDISK(romdisk);
/* storage for one texture */
int texture[1];
/* Image type - contains height, width, and data */
struct Image {
unsigned long sizeX;
unsigned long sizeY;
char *data;
};
typedef struct Image Image;
// quick and dirty bitmap loader...for 24 bit bitmaps with 1 plane only.
// See http://www.dcs.ed.ac.uk/~mxr/gfx/2d/BMP.txt for more info.
int ImageLoad(char *filename, Image *image) {
FILE *file;
unsigned long size; // size of the image in bytes.
unsigned long i; // standard counter.
unsigned short int planes; // number of planes in image (must be 1)
unsigned short int bpp; // number of bits per pixel (must be 24)
char temp; // temporary color storage for bgr-rgb conversion.
// make sure the file is there.
if ((file = fopen(filename, "rb"))==NULL)
{
printf("File Not Found : %s\n",filename);
return 0;
}
// seek through the bmp header, up to the width/height:
fseek(file, 18, SEEK_CUR);
// read the width
if ((i = fread(&image->sizeX, 4, 1, file)) != 1) {
printf("Error reading width from %s.\n", filename);
return 0;
}
printf("Width of %s: %lu\n", filename, image->sizeX);
// read the height
if ((i = fread(&image->sizeY, 4, 1, file)) != 1) {
printf("Error reading height from %s.\n", filename);
return 0;
}
printf("Height of %s: %lu\n", filename, image->sizeY);
// calculate the size (assuming 24 bits or 3 bytes per pixel).
size = image->sizeX * image->sizeY * 3;
// read the planes
if ((fread(&planes, 2, 1, file)) != 1) {
printf("Error reading planes from %s.\n", filename);
return 0;
}
if (planes != 1) {
printf("Planes from %s is not 1: %u\n", filename, planes);
return 0;
}
// read the bpp
if ((i = fread(&bpp, 2, 1, file)) != 1) {
printf("Error reading bpp from %s.\n", filename);
return 0;
}
if (bpp != 24) {
printf("Bpp from %s is not 24: %u\n", filename, bpp);
return 0;
}
// seek past the rest of the bitmap header.
fseek(file, 24, SEEK_CUR);
// read the data.
image->data = (char *) malloc(size);
if (image->data == NULL) {
printf("Error allocating memory for color-corrected image data");
return 0;
}
if ((i = fread(image->data, size, 1, file)) != 1) {
printf(stderr, "Error reading image data from %s.\n", filename);
return 0;
}
for (i=0;i<size;i+=3) { // reverse all of the colors. (bgr -> rgb)
temp = image->data[i];
image->data[i] = image->data[i+2];
image->data[i+2] = temp;
}
// we're done.
return 1;
}
// Load Bitmaps And Convert To Textures
void LoadGLTextures() {
// Load Texture
Image *image1;
// allocate space for texture
image1 = (Image *) malloc(sizeof(Image));
if (image1 == NULL) {
printf("Error allocating space for image");
exit(0);
}
if (!ImageLoad("/rd/NeHe.bmp", image1)) {
exit(1);
}
// Create Texture
glGenTextures(1, &texture[0]);
glBindTexture(GL_TEXTURE_2D, texture[0]); // 2d texture (x and y size)
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); // scale linearly when image bigger than texture
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_LINEAR); // scale linearly when image smalled than texture
// 2d texture, level of detail 0 (normal), 3 components (red, green, blue), x size from image, y size from image,
// border 0 (normal), rgb color data, unsigned byte data, and finally the data itself.
glTexImage2D(GL_TEXTURE_2D, 0, 3, image1->sizeX, image1->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, image1->data);
glGenerateMipmapEXT(GL_TEXTURE_2D);
};
/* A general OpenGL initialization function. Sets all of the initial parameters. */
void InitGL(int Width, int Height) // We call this right after our OpenGL window is created.
{
LoadGLTextures();
glEnable(GL_TEXTURE_2D);
glClearColor(0.0f, 0.0f, 0.0f, 0.0f); // This Will Clear The Background Color To Black
glClearDepth(1.0); // Enables Clearing Of The Depth Buffer
glDepthFunc(GL_LESS); // The Type Of Depth Test To Do
glEnable(GL_DEPTH_TEST); // Enables Depth Testing
glShadeModel(GL_SMOOTH); // Enables Smooth Color Shading
glMatrixMode(GL_PROJECTION);
glLoadIdentity(); // Reset The Projection Matrix
gluPerspective(45.0f,(GLfloat)Width/(GLfloat)Height,0.1f,100.0f); // Calculate The Aspect Ratio Of The Window
glMatrixMode(GL_MODELVIEW);
}
/* The function called when our window is resized (which shouldn't happen, because we're fullscreen) */
void ReSizeGLScene(int Width, int Height)
{
if (Height == 0) // Prevent A Divide By Zero If The Window Is Too Small
Height = 1;
glViewport(0, 0, Width, Height); // Reset The Current Viewport And Perspective Transformation
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(45.0f,(GLfloat)Width/(GLfloat)Height,0.1f,100.0f);
glMatrixMode(GL_MODELVIEW);
}
void DrawQuad() {
glBegin(GL_QUADS);
glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f, 0.0f); // Bottom Left Of The Texture and Quad
glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f, 0.0f); // Bottom Right Of The Texture and Quad
glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f, 1.0f, 0.0f); // Top Right Of The Texture and Quad
glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f, 1.0f, 0.0f); // Top Left Of The Texture and Quad
glEnd(); // done with the polygon.
}
/* The main drawing function. */
void DrawGLScene()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
glClearColor(0.5, 0.5, 0.5, 1.0);
glBindTexture(GL_TEXTURE_2D, texture[0]);
glTranslatef(-1.5f, 0.0f, -4.5f);
DrawQuad();
glTranslatef(1.0f, 0.0f, -5.0f);
DrawQuad();
glTranslatef(1.5f, 0.0f, -5.0f);
DrawQuad();
glTranslatef(2.0f, 0.0f, -5.0f);
DrawQuad();
glTranslatef(3.5f, 0.0f, -5.0f);
DrawQuad();
glKosSwapBuffers();
}
int main(int argc, char **argv)
{
glKosInit();
InitGL(640, 480);
ReSizeGLScene(640, 480);
while(1) {
DrawGLScene();
}
return 0;
}

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