opengl_learn

commit 6455b97b23ccf06f3dd8d4f42fd5e6cf83bda2e9
parent 90b09385b3aba47aa6963c9ff4bc162e0a07b913
Author: David DiPaola <DavidDiPaola@users.noreply.github.com>
Date:   Fri, 22 Jun 2018 18:12:16 -0400

03: alpha in textures should now show "underlying" fragment color

Diffstat:
M
03-texture.c
 | 
11
+++++------

1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/03-texture.c b/03-texture.c
@@ -35,9 +35,9 @@ main() {
 		"varying   vec4 varying_color;" "\n"       /* varyings are outputs of vertex shaders and inputs to fragment shaders */
 		"varying   vec2 varying_UV;" "\n"
 		"void main(){" "\n"
-		"	gl_Position = uniform_MVP * vec4(attribute_position,1);" "\n"
+		"	gl_Position   = uniform_MVP * vec4(attribute_position,1);" "\n"
 		"	varying_color = vec4(attribute_color,1);" "\n"
-		"	varying_UV = attribute_UV;" "\n"
+		"	varying_UV    = attribute_UV;" "\n"
 		"}" "\n"
 	;
 	const char * program_fragment_source =
@@ -47,9 +47,8 @@ main() {
 		"varying vec4      varying_color;" "\n"
 		"varying vec2      varying_UV;" "\n"
 		"void main() {" "\n"
-		//"	gl_FragColor = texture2D(uniform_texturesampler, varying_UV) * varying_color;" "\n"
-		"	gl_FragColor = texture2D(uniform_texturesampler, varying_UV);" "\n"
-		//"	gl_FragColor = varying_color;" "\n"
+		"	vec4 texturesampler_color = texture2D(uniform_texturesampler, varying_UV);" "\n"
+		"	gl_FragColor = mix(texturesampler_color, varying_color, 1.0-texturesampler_color.a);" "\n"
 		"}" "\n"
 	;
 	GLuint program_ID = ogl_program_build(program_vertex_source, program_fragment_source);
@@ -112,7 +111,7 @@ main() {
 	GLuint cube_colorbuffer_ID = ogl_arraybuffer_load(cube_colorbuffer_data, cube_colorbuffer_data_size);
 
 	uint32_t cube_texture_data[] = {
-		htobe32(0xFFFF00FF),  htobe32(0x0000FFFF),
+		htobe32(0x00000000),  htobe32(0x0000FFFF),
 		htobe32(0xFF0000FF),  htobe32(0x00FF00FF),
 	};
 	const size_t cube_texture_data_width  = 2;