From 0dcfa92e4cbedd3c56a9c266e934735f4ab60c6f Mon Sep 17 00:00:00 2001
From: capehill <juha.niemimaki@gmail.com>
Date: Sat, 26 Mar 2022 19:31:17 +0200
Subject: [PATCH] testgles2: Call correct function to get shader info log and
 add link status checking

---
 test/testgles2.c | 59 ++++++++++++++++++++++++++++++++----------------
 1 file changed, 39 insertions(+), 20 deletions(-)

diff --git a/test/testgles2.c b/test/testgles2.c
index 153ebe499..2000e01ec 100644
--- a/test/testgles2.c
+++ b/test/testgles2.c
@@ -38,6 +38,18 @@ typedef struct GLES2_Context
 #undef SDL_PROC
 } GLES2_Context;
 
+typedef struct shader_data
+{
+    GLuint shader_program, shader_frag, shader_vert;
+
+    GLint attr_position;
+    GLint attr_color, attr_mvp;
+
+    int angle_x, angle_y, angle_z;
+
+    GLuint position_buffer;
+    GLuint color_buffer;
+} shader_data;
 
 static SDLTest_CommonState *state;
 static SDL_GLContext *context = NULL;
@@ -197,13 +209,13 @@ multiply_matrix(float *lhs, float *rhs, float *r)
  * source: Passed-in shader source code.
  * shader_type: Passed to GL, e.g. GL_VERTEX_SHADER.
  */
-void 
+static void
 process_shader(GLuint *shader, const char * source, GLint shader_type)
 {
     GLint status = GL_FALSE;
     const char *shaders[1] = { NULL };
     char buffer[1024];
-    GLsizei length;
+    GLsizei length = 0;
 
     /* Create shader and load into GL. */
     *shader = GL_CHECK(ctx.glCreateShader(shader_type));
@@ -221,13 +233,35 @@ process_shader(GLuint *shader, const char * source, GLint shader_type)
 
     /* Dump debug info (source and log) if compilation failed. */
     if(status != GL_TRUE) {
-        ctx.glGetProgramInfoLog(*shader, sizeof(buffer), &length, &buffer[0]);
+        ctx.glGetShaderInfoLog(*shader, sizeof(buffer), &length, &buffer[0]);
         buffer[length] = '\0';
-        SDL_Log("Shader compilation failed: %s", buffer);fflush(stderr);
+        SDL_Log("Shader compilation failed: %s", buffer);
+        fflush(stderr);
         quit(-1);
     }
 }
 
+static void
+link_program(struct shader_data *data)
+{
+    GLint status = GL_FALSE;
+    char buffer[1024];
+    GLsizei length = 0;
+
+    GL_CHECK(ctx.glAttachShader(data->shader_program, data->shader_vert));
+    GL_CHECK(ctx.glAttachShader(data->shader_program, data->shader_frag));
+    GL_CHECK(ctx.glLinkProgram(data->shader_program));
+    GL_CHECK(ctx.glGetProgramiv(data->shader_program, GL_LINK_STATUS, &status));
+
+    if(status != GL_TRUE) {
+         ctx.glGetProgramInfoLog(data->shader_program, sizeof(buffer), &length, &buffer[0]);
+         buffer[length] = '\0';
+         SDL_Log("Program linking failed: %s", buffer);
+         fflush(stderr);
+         quit(-1);
+    }
+}
+
 /* 3D data. Vertex range -0.5..0.5 in all axes.
 * Z -0.5 is near, 0.5 is far. */
 const float _vertices[] =
@@ -363,19 +397,6 @@ const char* _shader_frag_src =
 "    gl_FragColor = vec4(vv3color, 1.0); "
 " } ";
 
-typedef struct shader_data
-{
-    GLuint shader_program, shader_frag, shader_vert;
-
-    GLint attr_position;
-    GLint attr_color, attr_mvp;
-
-    int angle_x, angle_y, angle_z;
-
-    GLuint position_buffer;
-    GLuint color_buffer;
-} shader_data;
-
 static void
 Render(unsigned int width, unsigned int height, shader_data* data)
 {
@@ -672,9 +693,7 @@ main(int argc, char *argv[])
         data->shader_program = GL_CHECK(ctx.glCreateProgram());
 
         /* Attach shaders and link shader_program */
-        GL_CHECK(ctx.glAttachShader(data->shader_program, data->shader_vert));
-        GL_CHECK(ctx.glAttachShader(data->shader_program, data->shader_frag));
-        GL_CHECK(ctx.glLinkProgram(data->shader_program));
+        link_program(data);
 
         /* Get attribute locations of non-fixed attributes like color and texture coordinates. */
         data->attr_position = GL_CHECK(ctx.glGetAttribLocation(data->shader_program, "av4position"));