opengl_learn

commit a549948ba1abaf0e31c98287d814e0ae6a6af125
parent ee9038b8f9840399e8da90e4a112cc5c57f0705a
Author: David DiPaola <DavidDiPaola@users.noreply.github.com>
Date:   Wed, 27 Jun 2018 08:20:24 -0400

01: updated shader variable names to match 02 and 03

Diffstat:
M
01-perspective.c
 | 
17
+++++++++--------

1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/01-perspective.c b/01-perspective.c
@@ -19,13 +19,14 @@ int
 main() {
 	GLFWwindow * window = ogl_init(400, 240, "01 - triangle with perspective");
 
+	/* vu: vertex shader uniform,  va: vertex shader attribute,  fu: fragment shader uniform,  fv: fragment shader varying */
 	const char * program_vertex_source =
 		"#version 100" "\n"
 		"precision highp float;" "\n"
-		"uniform   mat4 uniform_MVP;" "\n"         /* uniforms are inputs to vertex shaders that don't change per-vertex */
-		"attribute vec3 attribute_position;" "\n"  /* attributes are inputs to vertex shaders */
+		"uniform   mat4 vu_vertex_MVP;" "\n"       /* uniforms are inputs to vertex and fragment shaders that don't change per-vertex */
+		"attribute vec3 va_vertex_position;" "\n"  /* attributes are inputs to vertex shaders */
 		"void main(){" "\n"
-		"	gl_Position = uniform_MVP * vec4(attribute_position,1);" "\n"
+		"	gl_Position = vu_vertex_MVP * vec4(va_vertex_position,1);" "\n"
 		"}" "\n"
 	;
 	const char * program_fragment_source =
@@ -36,7 +37,7 @@ main() {
 		"}" "\n"
 	;
 	GLuint program_ID = ogl_program_build(program_vertex_source, program_fragment_source);
-	GLint program_attribute_position_ID = glGetAttribLocation(program_ID, "attribute_position");
+	GLint program_va_vertex_position_ID = glGetAttribLocation(program_ID, "va_vertex_position");
 
 	struct ogl_mat4f MVP_projection;
 	ogl_perspective(45.0f, 0.1f, 100.0f, &MVP_projection);
@@ -67,14 +68,14 @@ main() {
 		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
 		glUseProgram(program_ID);
-		ogl_program_uniform_set_mat4f(program_ID, "uniform_MVP", MVP);
+		ogl_program_uniform_set_mat4f(program_ID, "vu_vertex_MVP", MVP);
 
-		glEnableVertexAttribArray(program_attribute_position_ID);
+		glEnableVertexAttribArray(program_va_vertex_position_ID);
 		glBindBuffer(GL_ARRAY_BUFFER, triangle_vertexbuffer_ID);
-		glVertexAttribPointer(program_attribute_position_ID, 3, GL_FLOAT, GL_FALSE, 0, (GLvoid *)0);
+		glVertexAttribPointer(program_va_vertex_position_ID, 3, GL_FLOAT, GL_FALSE, 0, (GLvoid *)0);
 		glDrawArrays(GL_TRIANGLES, 0, triangle_vertexbuffer_data_vertexes);
 		glBindBuffer(GL_ARRAY_BUFFER, 0);
-		glDisableVertexAttribArray(program_attribute_position_ID);
+		glDisableVertexAttribArray(program_va_vertex_position_ID);
 
 		glfwSwapBuffers(window);
 		glfwPollEvents();