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-rw-r--r--sdl/GL_notes.txt6
-rw-r--r--sdl/gldraw.c8
-rw-r--r--sdl/platform.c81
-rw-r--r--sdl/platform.h14
-rw-r--r--sdl/pyramid.c26
5 files changed, 92 insertions, 43 deletions
diff --git a/sdl/GL_notes.txt b/sdl/GL_notes.txt
index 23795e9..ac51035 100644
--- a/sdl/GL_notes.txt
+++ b/sdl/GL_notes.txt
@@ -2,6 +2,9 @@ Performance
- Depth Testing, aka Z-buffer
- Culling: don't render what you can't see
+Ideas
+- Use scissor test or bind texture for HUD display?
+
Terms
- Winding: by default, primitives that follow in CCW fashion are front facing
@@ -36,7 +39,8 @@ Terms
- Dithering: simulate displaying wider range of colors on on systems with small
amount of colors
- Texture Filtering: process of calculating color fragments from a stretched or
- shrunken texture map
+ shrunken texture map
+ - Fragments: color values placed in the color buffer
OBJ Loader
- glGenTextures()
diff --git a/sdl/gldraw.c b/sdl/gldraw.c
index ed455e0..5430009 100644
--- a/sdl/gldraw.c
+++ b/sdl/gldraw.c
@@ -188,6 +188,10 @@ void glDrawTriangle(void)
void glDrawGround(void)
{
+ glDisable(GL_MULTISAMPLE);
+ glEnable(GL_BLEND);
+ glEnable(GL_LINE_SMOOTH);
+
GLfloat fExtent = 20.0f;
GLfloat fStep = 0.5f;
GLfloat y = -0.4f;
@@ -203,6 +207,10 @@ void glDrawGround(void)
glVertex3f(-fExtent, y, iLine);
}
glEnd();
+
+ glDisable(GL_LINE_SMOOTH);
+ glDisable(GL_BLEND);
+ glEnable(GL_MULTISAMPLE);
}
void glDrawUnitAxes(void)
diff --git a/sdl/platform.c b/sdl/platform.c
index 270a938..677b5b8 100644
--- a/sdl/platform.c
+++ b/sdl/platform.c
@@ -2,6 +2,7 @@
*
* Platform
*
+ * Notes: Assumes multisampling is always enabled
*
*/
@@ -11,15 +12,14 @@
#include "platform.h"
/* few light arrays */
-GLfloat fNoLight[] = { 0.0f, 0.0f, 0.0f, 0.0f };
-GLfloat fLowLight[] = { 0.25f, 0.25f, 0.25f, 1.0f };
-GLfloat fMedLight[] = { 0.50f, 0.50f, 0.50f, 1.0f };
-GLfloat fBrightLight[] = { 1.0f, 1.0f, 1.0f, 1.0f };
+const GLfloat fNoLight[] = { 0.0f, 0.0f, 0.0f, 1.0f };
+const GLfloat fLowLight[] = { 0.25f, 0.25f, 0.25f, 1.0f };
+const GLfloat fMedLight[] = { 0.50f, 0.50f, 0.50f, 1.0f };
+const GLfloat fShinyLight[] = { 0.70f, 0.70f, 0.70f, 1.0f };
+const GLfloat fBrightLight[] = { 1.0f, 1.0f, 1.0f, 1.0f };
/* light values and coordinates */
-GLfloat whiteLight[] = { 0.05f, 0.05f, 0.05f, 1.0f };
-GLfloat sourceLight[] = { 0.75f, 0.75f, 0.75f, 1.0f };
-GLfloat lightPos[] = { -10.f, 5.0f, 5.0f, 1.0f };
+const GLfloat lightPos[] = { -10.f, 5.0f, 5.0f, 1.0f };
/* variables that should be already defined and declared for us by main program */
extern const unsigned int xres_w;
@@ -38,47 +38,74 @@ void setup_opengl(void)
glFogf(GL_FOG_END, 20.0f);
glFogi(GL_FOG_MODE, GL_LINEAR); /* fog equation */
- glEnable(GL_DEPTH_TEST); /* hidden surface removal */
+ glEnable(GL_DEPTH_TEST); /* hidden surface removal, aka Z-buffer */
glFrontFace(GL_CCW); /* counter clock-wise polygons face out */
glEnable(GL_CULL_FACE); /* do not calculate inside of a pyramid */
- /* enable lighting */
+ /* enable lighting, primitives now need to define color properties */
glEnable(GL_LIGHTING);
/* global illumination, ambient RGBA intensity of the entire scene */
glLightModelfv(GL_LIGHT_MODEL_AMBIENT, fLowLight);
/* setup and enable light 0 */
- glLightfv(GL_LIGHT0, GL_AMBIENT, fMedLight);
- glLightfv(GL_LIGHT0, GL_DIFFUSE, fMedLight);
+ glLightfv(GL_LIGHT0, GL_AMBIENT, fMedLight);
+ glLightfv(GL_LIGHT0, GL_DIFFUSE, fShinyLight);
glLightfv(GL_LIGHT0, GL_SPECULAR, fBrightLight);
glLightfv(GL_LIGHT0, GL_POSITION, lightPos);
glEnable(GL_LIGHT0);
- /* enable color tracking */
- glEnable(GL_COLOR_MATERIAL);
-
- /* set material properties to follow glColor values */
+ /* set material properties to follow all glColor values */
/* all primitives specified after the glMaterial call are affected by the
* last values set, until another call to glMaterial is made */
glColorMaterial(GL_FRONT, GL_AMBIENT_AND_DIFFUSE);
+
+ /* enable color tracking, should be called after glColorMaterial */
+ glEnable(GL_COLOR_MATERIAL);
+
+ /* set globally, sets specular reflection to a white color,
+ * this call follows all subsequent primitives */
glMaterialfv(GL_FRONT, GL_SPECULAR, fBrightLight);
- glMateriali(GL_FRONT, GL_SHININESS, 128);
- /* turn on anti aliasing for points, lines, and polygons */
+ /* default (0), by increasing this value you reduce the size and increase
+ * the focus of the specular highlight, causing a shiny spot to appear */
+ glMateriali(GL_FRONT, GL_SHININESS, 64);
+
+ /* multisampling for polygons, conflicts with *polygon* anti-aliasing */
+ /* enabled by default, that's what man page says, hmmm! */
+ glEnable(GL_MULTISAMPLE);
+
+ if (glIsEnabled(GL_MULTISAMPLE) == GL_FALSE)
+ {
+ fprintf(stderr, "OpenGL error: multisampling cannot be enabled!\n");
+ exit(-1);
+ }
+
+ /* turn off AA forever, it enables blending globally, so depth test goes out
+ * of the window, blended objects should be rendered in back to front order,
+ * also, following lines are ignored by OpenGL if multisampling is enabled */
+#if 0
+ /* turn on anti aliasing for points and lines */
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_BLEND);
glEnable(GL_POINT_SMOOTH);
glHint(GL_POINT_SMOOTH_HINT, GL_NICEST);
glEnable(GL_LINE_SMOOTH);
glHint(GL_LINE_SMOOTH_HINT, GL_NICEST);
+#endif
- /* screws up snowman, this has been replaced by superior multisampling */
- //glEnable(GL_POLYGON_SMOOTH);
- //glHint(GL_POLYGON_SMOOTH_HINT, GL_NICEST);
+ /* we will keep the blending function and hints though */
+ glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+ glHint(GL_POINT_SMOOTH_HINT, GL_NICEST);
+ glHint(GL_LINE_SMOOTH_HINT, GL_NICEST);
- /* multisampling for polygons, conflicts with *polygon* anti-aliasing */
- glEnable(GL_MULTISAMPLE);
+ /* XXX: anisotropic filtering */
+
+#if 0
+ /* screws up snowman, this has been replaced by superior multisampling */
+ glEnable(GL_POLYGON_SMOOTH);
+ glHint(GL_POLYGON_SMOOTH_HINT, GL_NICEST);
+#endif
/* how OpenGL combines the colors from texels with the color of the underlying
* geometry is controlled by the texture environment mode */
@@ -88,8 +115,11 @@ void setup_opengl(void)
* that specifies coordinates, ORLY? */
glEnable(GL_TEXTURE_2D);
- /* don't know about this, but why not */
+ /* specular highlights for textured items */
glLightModeli(GL_LIGHT_MODEL_COLOR_CONTROL, GL_SEPARATE_SPECULAR_COLOR);
+ /* glLightModeli(GL_LIGHT_MODEL_COLOR_CONTROL, GL_COLOR_SINGLE); */
+ /* only if lighting is disabled */
+ /* glEnable(GL_COLOR_SUM); */
/* gray background */
glClearColor(0.5f, 0.5f, 0.5f, 1.0f);
@@ -127,7 +157,7 @@ SDL_Surface *setup_sdl_video(int w, int h, int bpp, unsigned int flags)
return srfc;
}
-void setup_sdl(void)
+SDL_Surface *setup_sdl(void)
{
SDL_Surface *screen;
const SDL_VideoInfo* info = NULL;
@@ -194,6 +224,7 @@ void setup_sdl(void)
SDL_PushEvent(&resizeEvent);
/* save the surf pointer in platform */
+ return screen;
}
void setup_glew(void)
@@ -213,6 +244,6 @@ void setup_glew(void)
GLint minor;
glGetIntegerv(GL_MAJOR_VERSION, &major);
glGetIntegerv(GL_MINOR_VERSION, &minor);
- fprintf(stdout, "GLEW: detected OpenGL %d.%d\n", major, minor);
+ fprintf(stdout, "GLEW: initialized OpenGL %d.%d\n", major, minor);
}
diff --git a/sdl/platform.h b/sdl/platform.h
index 8be6052..09028d1 100644
--- a/sdl/platform.h
+++ b/sdl/platform.h
@@ -1,18 +1,16 @@
#ifndef _PLATFORM_H_
#define _PLATFORM_H_
-extern GLfloat fNoLight[];
-extern GLfloat fLowLight[];
-extern GLfloat fBrightLight[];
-
-extern GLfloat whiteLight[];
-extern GLfloat sourceLight[];
-extern GLfloat lightPos[];
+extern const GLfloat fNoLight[];
+extern const GLfloat fLowLight[];
+extern const GLfloat fShinyLight[];
+extern const GLfloat fBrightLight[];
+extern const GLfloat lightPos[];
/* function prototypes */
void setup_opengl(void);
SDL_Surface *setup_sdl_video(int, int, int, unsigned int);
-void setup_sdl(void);
+SDL_Surface *setup_sdl(void);
void setup_glew(void);
#endif
diff --git a/sdl/pyramid.c b/sdl/pyramid.c
index 4fb2b6a..42c7a22 100644
--- a/sdl/pyramid.c
+++ b/sdl/pyramid.c
@@ -61,6 +61,9 @@ static struct
GLfloat xrot;
GLfloat yrot;
+ /* SDL surface, our screen */
+ SDL_Surface *screen;
+
SDL_TimerID timer_id;
SDL_Cursor *my_cursor;
} p;
@@ -173,20 +176,20 @@ static void platform_init(void)
p.ground_list = glGenLists(2);
p.triangle_list = p.ground_list + 1;
- /* a ground with grass drawn using magneta lines */
- glNewList(p.ground_list, GL_COMPILE);
- //glBindTexture(GL_TEXTURE_2D, p.textures[1]);
- glColor3ub(255, 0, 255);
- glDrawGround();
- glEndList();
-
/* a triangle with a texture */
glNewList(p.triangle_list, GL_COMPILE);
glBindTexture(GL_TEXTURE_2D, p.textures[0]);
+ /* glBindTexture(GL_TEXTURE_2D, p.textures[1]); */
glColor3f(1.0f, 1.0f, 1.0f);
glDrawTriangle();
glEndList();
+ /* a ground drawn using magneta lines */
+ glNewList(p.ground_list, GL_COMPILE);
+ glColor3ub(255, 0, 255);
+ glDrawGround();
+ glEndList();
+
/* add a simple timer / callback function */
p.timer_id = SDL_AddTimer(5000, sdlTimerCallback, &(p.camera));
@@ -199,6 +202,8 @@ static void platform_destroy(void)
{
glDeleteTextures(2, p.textures);
glDeleteLists(p.ground_list, 2);
+
+ SDL_FreeSurface(p.screen);
}
static void render(void)
@@ -210,7 +215,6 @@ static void render(void)
glPushMatrix();
/* apply camera transform, and draw the ground */
glframe_apply_camera_transform(&p.camera, 1);
-
glCallList(p.ground_list);
glPushMatrix();
@@ -225,7 +229,10 @@ static void render(void)
/* draw a snowman */
glTranslatef(0.0f, 0.0f, -7.0f);
+
+ glDisable(GL_TEXTURE_2D);
glDrawSnowman();
+ glEnable(GL_TEXTURE_2D);
/* restore the matrix state */
glPopMatrix();
@@ -236,11 +243,12 @@ static void render(void)
int main(int argc, char **argv)
{
- setup_sdl();
+ p.screen = setup_sdl();
setup_glew();
setup_opengl();
platform_init();
gltErrorCheck();
+ gltOpenGLInfo();
unsigned int startclock;
while (program_running)
generated by cgit v1.2.3 (git 2.25.1) at 2025-11-04 14:19:55 +0000