diff --git a/src/args.c b/src/args.c
index 0cdd152..b42d3b2 100644
--- a/src/args.c
+++ b/src/args.c
@@ -85,7 +85,7 @@ static bool is_arg(const char *arg, const char *ref) {
   return strcoll(arg, ref) == 0;
 }
 
-static char *split_arg_value(char *arg) {
+static const char *split_arg_value(char *arg) {
   char *rest;
 
   strtok_r(arg, "=", &rest);
@@ -111,7 +111,7 @@ static unsigned int parse_uint(const char *arg, const char *value) {
 
 void args_parse(Parameters *params, int argc, char **argv) {
   char *arg;
-  char *value;
+  const char *value;
 
   strlcpy(params->project_path, DATADIR "/default", STR_LEN);
   strlcpy(params->config_file, "forge_project.cfg", STR_LEN);
diff --git a/src/config_file.c b/src/config_file.c
index 0e773ec..a3bf6de 100644
--- a/src/config_file.c
+++ b/src/config_file.c
@@ -117,7 +117,7 @@ unsigned int config_file_get_int(const ConfigFile *config, const char *key,
     return default_value;
   }
 
-  if (!string_is_number((char *)item->value)) {
+  if (!string_is_number(item->value)) {
     log_warn("Invalid number for %s: '%s'", item->key, item->value);
     return default_value;
   }
diff --git a/src/project.c b/src/project.c
index 69e27f5..7c01790 100644
--- a/src/project.c
+++ b/src/project.c
@@ -14,8 +14,8 @@
 static bool parse_fragment_shader_file(Project *project, unsigned int i) {
   File tmp_file;
   char file_path[STR_LEN];
-  char *include_pos;
-  char *include_end;
+  const char *include_pos;
+  const char *include_end;
   char included_file[STR_LEN];
   char *new_content;
 
diff --git a/src/shaders.c b/src/shaders.c
index 2d3e70d..445d686 100644
--- a/src/shaders.c
+++ b/src/shaders.c
@@ -62,7 +62,7 @@ static void init_textures(ShaderProgram *program,
   }
 }
 
-static void rebind_textures(ShaderProgram *program) {
+static void rebind_textures(const ShaderProgram *program) {
   for (unsigned int i = 0; i < program->tex_count; i++) {
     glActiveTexture(GL_TEXTURE0 + i);
     glBindTexture(GL_TEXTURE_2D, program->textures[i]);
@@ -88,9 +88,9 @@ static void link_input_to_texture(ShaderProgram *program, VideoCapture *input,
                                 input->bytesperline,
                                 EGL_NONE};
 
-  input->dma_image = eglCreateImageKHR(program->egl_display, EGL_NO_CONTEXT,
-                                       EGL_LINUX_DMA_BUF_EXT,
-                                       (EGLClientBuffer)NULL, attrib_list);
+  input->dma_image =
+      eglCreateImageKHR(program->egl_display, EGL_NO_CONTEXT,
+                        EGL_LINUX_DMA_BUF_EXT, NULL, attrib_list);
 
   if (input->dma_image == EGL_NO_IMAGE_KHR) {
     log_error("(%s) eglCreateImageKHR failed %04x", input->name, eglGetError());
@@ -105,8 +105,7 @@ static void link_input_to_texture(ShaderProgram *program, VideoCapture *input,
                GL_UNSIGNED_BYTE, 0);
 
   // https://registry.khronos.org/OpenGL/extensions/EXT/EXT_EGL_image_storage.txt
-  glEGLImageTargetTexStorageEXT(GL_TEXTURE_2D, (GLeglImageOES)input->dma_image,
-                                NULL);
+  glEGLImageTargetTexStorageEXT(GL_TEXTURE_2D, input->dma_image, NULL);
 
   log_info("Texture %d linked to %s", texture_index, input->name);
 }
@@ -192,7 +191,7 @@ static bool compile_shader(GLuint shader_id, const char *name,
   log_info("Compiling '%s'...", name);
 
   // update shader source code
-  glShaderSource(shader_id, 1, (const GLchar **)&source_code, NULL);
+  glShaderSource(shader_id, 1, &source_code, NULL);
 
   // compile shader
   glCompileShader(shader_id);
@@ -214,15 +213,17 @@ static bool compile_shader(GLuint shader_id, const char *name,
 static void init_shaders(ShaderProgram *program, const Project *project) {
   // compile vertex shader
   program->vertex_shader = glCreateShader(GL_VERTEX_SHADER);
-  program->error |= !compile_shader(
-      program->vertex_shader, "internal vertex shader", vertex_shader_text);
+  program->error = program->error || !compile_shader(program->vertex_shader,
+                                                     "internal vertex shader",
+                                                     vertex_shader_text);
 
   // compile fragment shaders
   for (unsigned int i = 0; i < program->frag_count; i++) {
     program->fragment_shaders[i] = glCreateShader(GL_FRAGMENT_SHADER);
-    program->error |= !compile_shader(program->fragment_shaders[i],
-                                      project->fragment_shaders[i][0].path,
-                                      project->fragment_shaders[i][0].content);
+    program->error = program->error ||
+                     !compile_shader(program->fragment_shaders[i],
+                                     project->fragment_shaders[i][0].path,
+                                     project->fragment_shaders[i][0].content);
 
     if (program->error) {
       return;
@@ -422,7 +423,7 @@ void shaders_init(ShaderProgram *program, const Project *project,
   ;
 }
 
-void shaders_update(ShaderProgram *program, const File *fragment_shader,
+void shaders_update(const ShaderProgram *program, const File *fragment_shader,
                     unsigned int i) {
   bool result;
 
@@ -454,7 +455,7 @@ static void update_viewport(ShaderProgram *program,
 
 static void write_uniform_1f(GLuint location, float value) {
   if (location != unused_uniform) {
-    glUniform1f(location, (const GLfloat)value);
+    glUniform1f(location, value);
   }
 }
 
diff --git a/src/shaders.h b/src/shaders.h
index 68d4a97..a71bbb8 100644
--- a/src/shaders.h
+++ b/src/shaders.h
@@ -7,7 +7,7 @@ void shaders_init(ShaderProgram *program, const Project *project,
                   const SharedContext *context, VideoCaptureArray *inputs,
                   bool rebind);
 
-void shaders_update(ShaderProgram *program, const File *fragment_shader,
+void shaders_update(const ShaderProgram *program, const File *fragment_shader,
                     unsigned int i);
 
 void shaders_compute(ShaderProgram *program, const SharedContext *context,