commit ee58f2467a97b3bef00983089ac947e7420cfe38
parent ebec8290bd023f5cac868dbd5f0325e5b763d9de
Author: David DiPaola <DavidDiPaola@users.noreply.github.com>
Date: Sun, 10 Jun 2018 11:49:48 -0400
ogl: perspective() now exists on error to make caller code simpler
Diffstat:
4 files changed, 28 insertions(+), 19 deletions(-)
diff --git a/01-perspective.c b/01-perspective.c
@@ -17,8 +17,6 @@ licensed under CC0 (public domain, see https://creativecommons.org/publicdomain/
int
main() {
- int status;
-
GLFWwindow * window = ogl_init(400, 240, "01 - triangle with perspective");
const char * program_vertex_source =
@@ -41,11 +39,7 @@ main() {
GLint program_attribute_position_ID = glGetAttribLocation(program_ID, "attribute_position");
struct ogl_mat4f MVP_projection;
- status = ogl_perspective(45.0f, 0.1f, 100.0f, &MVP_projection);
- if (status < 0) {
- fprintf(stderr, "\t" "at %s : %d" "\n", __FILE__, __LINE__);
- return status;
- }
+ ogl_perspective(45.0f, 0.1f, 100.0f, &MVP_projection);
struct ogl_mat4f MVP_view;
struct ogl_vec3f MVP_view_eye = { .x= 4.0f, .y= 3.0f, .z= 3.0f };
diff --git a/02-cube.c b/02-cube.c
@@ -17,8 +17,6 @@ licensed under CC0 (public domain, see https://creativecommons.org/publicdomain/
int
main() {
- int status;
-
GLFWwindow * window = ogl_init(400, 240, "02 - cube");
const char * program_vertex_source =
@@ -46,11 +44,7 @@ main() {
GLint program_attribute_color_ID = glGetAttribLocation(program_ID, "attribute_color");
struct ogl_mat4f MVP_projection;
- status = ogl_perspective(45.0f, 0.1f, 100.0f, &MVP_projection);
- if (status < 0) {
- fprintf(stderr, "\t" "at %s : %d" "\n", __FILE__, __LINE__);
- return status;
- }
+ ogl_perspective(45.0f, 0.1f, 100.0f, &MVP_projection);
struct ogl_mat4f MVP_view;
struct ogl_vec3f MVP_view_eye = { .x= 4.0f, .y= 3.0f, .z=-3.0f };
diff --git a/ogl/ogl.h b/ogl/ogl.h
@@ -126,7 +126,7 @@ ogl_lookat(
struct ogl_mat4f * out_matrix
);
-int
+void
ogl_perspective(
GLfloat fovy, GLfloat zNear, GLfloat zFar,
struct ogl_mat4f * out_matrix
diff --git a/ogl/ogl_perspective.c b/ogl/ogl_perspective.c
@@ -3,6 +3,10 @@
licensed under CC0 (public domain, see https://creativecommons.org/publicdomain/zero/1.0/)
*/
+#include <stdio.h>
+
+#include <stdlib.h>
+
#include <GL/glew.h>
#include <math.h>
@@ -10,16 +14,34 @@ licensed under CC0 (public domain, see https://creativecommons.org/publicdomain/
#include "ogl.h"
#include "_ogl.h"
-int
+void
ogl_perspective(
GLfloat fovy, GLfloat zNear, GLfloat zFar,
struct ogl_mat4f * out_matrix
) {
/* from https://www.khronos.org/registry/OpenGL-Refpages/gl2.1/xhtml/gluPerspective.xml */
+
GLfloat aspect = (GLfloat)_ogl_window_width / (GLfloat)_ogl_window_height;
- if ((fovy < 0.0f) || (aspect < 0.0f) || (zNear < 0.0f) || (zFar < 0.0f) || (zNear > zFar)) {
- return -1;
+ if (fovy < 0.0f) {
+ fprintf(stderr, "ogl:perspective() ERROR: fovy < 0.0f (is %g)" "\n", fovy);
+ exit(-1);
+ }
+ if (aspect < 0.0f) {
+ fprintf(stderr, "ogl:perspective() ERROR: aspect < 0.0f (is %g)" "\n", aspect);
+ exit(-1);
+ }
+ if (zNear < 0.0f) {
+ fprintf(stderr, "ogl:perspective() ERROR: zNear < 0.0f (is %g)" "\n", zNear);
+ exit(-1);
+ }
+ if (zFar < 0.0f) {
+ fprintf(stderr, "ogl:perspective() ERROR: zFar < 0.0f (is %g)" "\n", zFar);
+ exit(-1);
+ }
+ if (zNear > zFar) {
+ fprintf(stderr, "ogl:perspective() ERROR: zNear > zFar (%g > %g)" "\n", zNear, zFar);
+ exit(-1);
}
GLfloat f = 1.0f / tanf(fovy / 2.0f);
@@ -29,6 +51,5 @@ ogl_perspective(
values[ 4] = 0.0f; values[ 5] = f; values[ 6] = 0.0f; values[ 7] = 0.0f;
values[ 8] = 0.0f; values[ 9] = 0.0f; values[10] = (zFar+zNear) / (zNear-zFar); values[11] = (2*zFar*zNear) / (zNear-zFar);
values[12] = 0.0f; values[13] = 0.0f; values[14] = -1.0f; values[15] = 0.0f;
- return 0;
}
