output: add shader support

To avoid the fixed function pipeline we should use shaders instead of
old glBegin/glEnd. This patch adds two basic shaders and functions that
load and initialize them.

To avoid loading the shaders at runtime we generate a source file which
contains them as strings so they are embedded in the binary.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>

6 files changed, 457 insertions, 2 deletions

diff --git a/.gitignore b/.gitignore
index 8febbb8..d946916 100644
--- a/.gitignore
+++ b/.gitignore
@@ -22,3 +22,5 @@ stamp-*
 .deps
 .dirstamp
 .libs
+genshader
+src/output_shaders.c
diff --git a/Makefile.am b/Makefile.am
index 7b6b9b0..a7538ef 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,8 +1,11 @@
 ACLOCAL_AMFLAGS = -I m4
+EXTRA_DIST = README TODO COPYING
+CLEANFILES =
 
 bin_PROGRAMS = kmscon
 check_PROGRAMS = test_console test_output test_vt test_buffer test_terminal \
 	test_input
+noinst_PROGRAMS = genshader
 noinst_LTLIBRARIES = libkmscon-core.la
 
 AM_CFLAGS = \
@@ -19,6 +22,18 @@ else
 AM_CFLAGS += -O2
 endif
 
+EXTRA_DIST += src/output_shader.vert src/output_shader.frag
+CLEANFILES += src/output_shaders.c
+
+genshader_SOURCES = \
+	src/genshader.c
+
+src/output_shaders.c: src/output_shader.vert src/output_shader.frag genshader$(EXEEXT)
+	./genshader$(EXEEXT) src/output_shaders.c src/output_shader.vert src/output_shader.frag
+
+nodist_libkmscon_core_la_SOURCES = \
+	src/output_shaders.c
+
 libkmscon_core_la_SOURCES = \
 	src/console.c src/console.h \
 	src/output.c src/output.h \
@@ -99,5 +114,3 @@ test_input_LDADD = \
 test_input_CPPFLAGS = \
 	$(AM_CPPFLAGS) \
 	$(XKBCOMMON_CFLAGS)
-
-EXTRA_DIST = README TODO COPYING
diff --git a/src/genshader.c b/src/genshader.c
new file mode 100644
index 0000000..25c7bf7
--- /dev/null
+++ b/src/genshader.c
@@ -0,0 +1,141 @@
+/*
+ * kmscon - Generate Shader Files
+ *
+ * Copyright (c) 2011 David Herrmann <dh.herrmann@googlemail.com>
+ * Copyright (c) 2011 University of Tuebingen
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+/*
+ * Shader Generator
+ * This takes as arguments two shaders and creates a C-source file which
+ * contains these shaders as constants.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+static char *read_file(const char *path, size_t *size)
+{
+	FILE *ffile;
+	ssize_t len;
+	char *buf;
+
+	ffile = fopen(path, "rb");
+	if (!ffile) {
+		fprintf(stderr, "genshader: cannot open %s: %m\n", path);
+		abort();
+	}
+
+	if (fseek(ffile, 0, SEEK_END) != 0) {
+		fprintf(stderr, "genshader: cannot seek %s: %m\n", path);
+		abort();
+	}
+
+	len = ftell(ffile);
+	if (len < 0) {
+		fprintf(stderr, "genshader: cannot tell %s: %m\n", path);
+		abort();
+	}
+
+	if (len < 1) {
+		fprintf(stderr, "genshader: empty file %s\n", path);
+		abort();
+	}
+
+	rewind(ffile);
+
+	buf = malloc(len + 1);
+	if (!buf) {
+		fprintf(stderr, "genshader: memory allocation failed\n");
+		abort();
+	}
+
+	if (len != fread(buf, 1, len, ffile)) {
+		fprintf(stderr, "genshader: cannot read %s: %m\n", path);
+		abort();
+	}
+
+	buf[len] = 0;
+	*size = len;
+	fclose(ffile);
+
+	return buf;
+}
+
+static void write_seq(FILE *out, const char *src, size_t len)
+{
+	size_t i;
+
+	for (i = 0; i < len; ++i) {
+		if (src[i] == '\n') {
+			fwrite("\\n\"\n\"", 5, 1, out);
+		} else if (src[i] == '"') {
+			fwrite("\\\"", 2, 1, out);
+		} else {
+			fwrite(&src[i], 1, 1, out);
+		}
+	}
+}
+
+static void write_file(const char *path, const char *vs, size_t l1,
+						const char *fs, size_t l2)
+{
+	FILE *out;
+	static const char c1[] = "/* This file is generated by genshader.c */\n"
+	"const char *kmscon_vert_shader = \"";
+	static const char c2[] = "\";\nconst char *kmscon_frag_shader = \"";
+	static const char c3[] = "\";";
+
+	out = fopen(path, "wb");
+	if (!out) {
+		fprintf(stderr, "genshader: cannot open %s: %m\n", path);
+		abort();
+	}
+
+	fwrite(c1, sizeof(c1) - 1, 1, out);
+	write_seq(out, vs, l1);
+	fwrite(c2, sizeof(c2) - 1, 1, out);
+	write_seq(out, fs, l2);
+	fwrite(c3, sizeof(c3) - 1, 1, out);
+
+	fclose(out);
+}
+
+int main(int argc, char *argv[])
+{
+	char *vert, *frag;
+	size_t vs, fs;
+
+	if (argc < 4) {
+		fprintf(stderr, "genshader: missing parameters\n");
+		return EXIT_FAILURE;
+	}
+
+	vert = read_file(argv[2], &vs);
+	frag = read_file(argv[3], &fs);
+
+	write_file(argv[1], vert, vs, frag, fs);
+	free(vert);
+	free(frag);
+
+	return EXIT_SUCCESS;
+}
diff --git a/src/output_context.c b/src/output_context.c
index 8815083..ded82fd 100644
--- a/src/output_context.c
+++ b/src/output_context.c
@@ -43,20 +43,86 @@
 #include "log.h"
 #include "output.h"
 
+/* OpenGL extension definitions */
+typedef void (*PFNGLGENRENDERBUFFERSPROC)
+					(GLsizei n, GLuint *renderbuffers);
+typedef void (*PFNGLBINDRENDERBUFFERPROC)
+					(GLenum target, GLuint renderbuffer);
+typedef void (*PFNGLDELETERENDERBUFFERSPROC)
+				(GLsizei n, const GLuint *renderbuffers);
+
+typedef void (*PFNGLFRAMEBUFFERRENDERBUFFERPROC) (GLenum target,
+	GLenum attachment, GLenum renderbuffertarget, GLuint renderbuffer);
+typedef GLenum (*PFNGLCHECKFRAMEBUFFERSTATUSPROC) (GLenum target);
+typedef void (*PFNGLGENFRAMEBUFFERSPROC)
+					(GLsizei n, GLuint *framebuffers);
+typedef void (*PFNGLBINDFRAMEBUFFERPROC)
+					(GLenum target, GLuint framebuffer);
+typedef void (*PFNGLDELETEFRAMEBUFFERSPROC)
+				(GLsizei n, const GLuint *framebuffers);
+
+typedef GLuint (*PFNGLCREATESHADERPROC) (GLenum type);
+typedef void (*PFNGLDELETESHADERPROC) (GLuint shader);
+typedef void (*PFNGLGETSHADERSOURCEPROC)
+	(GLuint shader, GLsizei bufSize, GLsizei *length, GLchar *source);
+typedef void (*PFNGLCOMPILESHADERPROC) (GLuint shader);
+typedef void (*PFNGLGETSHADERIVPROC)
+				(GLuint shader, GLenum pname, GLint *params);
+typedef void (*PFNGLGETSHADERINFOLOGPROC)
+	(GLuint shader, GLsizei bufSize, GLsizei *length, GLchar *infoLog);
+
+typedef GLuint (*PFNGLCREATEPROGRAMPROC) (void);
+typedef void (*PFNGLDELETEPROGRAMPROC) (GLuint program);
+typedef void (*PFNGLATTACHSHADERPROC) (GLuint program, GLuint shader);
+typedef void (*PFNGLBINDATTRIBLOCATIONPROC)
+			(GLuint program, GLuint index, const GLchar *name);
+typedef void (*PFNGLLINKPROGRAMPROC) (GLuint program);
+typedef void (*PFNGLGETPROGRAMIVPROC)
+				(GLuint program, GLenum pname, GLint *params);
+typedef void (*PFNGLGETPROGRAMINFOLOGPROC)
+	(GLuint program, GLsizei bufSize, GLsizei *length, GLchar *infoLog);
+typedef GLint (*PFNGLGETUNIFORMLOCATIONPROC)
+					(GLuint program, const GLchar *name);
+
 struct kmscon_context {
 	EGLDisplay display;
 	EGLContext context;
+
+	GLuint program;
+	GLuint vshader;
+	GLuint fshader;
+	GLuint uni_projection;
+	GLuint uni_texture;
+
 	PFNGLEGLIMAGETARGETRENDERBUFFERSTORAGEOESPROC proc_rbuf_storage;
 	PFNEGLCREATEIMAGEKHRPROC proc_create_image;
 	PFNEGLDESTROYIMAGEKHRPROC proc_destroy_image;
+
 	PFNGLGENRENDERBUFFERSPROC proc_gen_renderbuffers;
 	PFNGLBINDRENDERBUFFERPROC proc_bind_renderbuffer;
 	PFNGLDELETERENDERBUFFERSPROC proc_delete_renderbuffers;
+
 	PFNGLFRAMEBUFFERRENDERBUFFERPROC proc_framebuffer_renderbuffer;
 	PFNGLCHECKFRAMEBUFFERSTATUSPROC proc_check_framebuffer_status;
 	PFNGLGENFRAMEBUFFERSPROC proc_gen_framebuffers;
 	PFNGLBINDFRAMEBUFFERPROC proc_bind_framebuffer;
 	PFNGLDELETEFRAMEBUFFERSPROC proc_delete_framebuffers;
+
+	PFNGLCREATESHADERPROC proc_create_shader;
+	PFNGLDELETESHADERPROC proc_delete_shader;
+	PFNGLSHADERSOURCEPROC proc_shader_source;
+	PFNGLCOMPILESHADERPROC proc_compile_shader;
+	PFNGLGETSHADERIVPROC proc_get_shader_iv;
+	PFNGLGETSHADERINFOLOGPROC proc_get_shader_info_log;
+
+	PFNGLCREATEPROGRAMPROC proc_create_program;
+	PFNGLDELETEPROGRAMPROC proc_delete_program;
+	PFNGLATTACHSHADERPROC proc_attach_shader;
+	PFNGLBINDATTRIBLOCATIONPROC proc_bind_attrib_location;
+	PFNGLLINKPROGRAMPROC proc_link_program;
+	PFNGLGETPROGRAMIVPROC proc_get_program_iv;
+	PFNGLGETPROGRAMINFOLOGPROC proc_get_program_info_log;
+	PFNGLGETUNIFORMLOCATIONPROC proc_get_uniform_location;
 };
 
 struct renderbuffer {
@@ -93,6 +159,95 @@ static bool has_gl_error()
 	return glGetError() != GL_NO_ERROR;
 }
 
+/* external shader sources; generated during build */
+extern const char *kmscon_vert_shader;
+extern const char *kmscon_frag_shader;
+
+static int compile_shader(struct kmscon_context *ctx, GLenum type,
+							const char *source)
+{
+	char msg[512];
+	GLint status = 1;
+	GLuint s;
+
+	s = ctx->proc_create_shader(type);
+	ctx->proc_shader_source(s, 1, &source, NULL);
+	ctx->proc_compile_shader(s);
+
+	ctx->proc_get_shader_iv(s, GL_COMPILE_STATUS, &status);
+	if (status == GL_FALSE) {
+		msg[0] = 0;
+		ctx->proc_get_shader_info_log(s, sizeof(msg), NULL, msg);
+		log_warning("context: cannot compile shader: %s\n", msg);
+		return GL_NONE;
+	}
+
+	return s;
+}
+
+static int init_shader(struct kmscon_context *ctx)
+{
+	char msg[512];
+	GLint status = 1;
+	int ret;
+
+	if (!ctx)
+		return -EINVAL;
+
+	ctx->vshader = compile_shader(ctx, GL_VERTEX_SHADER,
+							kmscon_vert_shader);
+	if (ctx->vshader == GL_NONE)
+		return -EFAULT;
+
+	ctx->fshader = compile_shader(ctx, GL_FRAGMENT_SHADER,
+							kmscon_frag_shader);
+	if (ctx->fshader == GL_NONE) {
+		ret = -EFAULT;
+		goto err_vshader;
+	}
+
+	ctx->program = ctx->proc_create_program();
+	ctx->proc_attach_shader(ctx->program, ctx->vshader);
+	ctx->proc_attach_shader(ctx->program, ctx->fshader);
+	ctx->proc_bind_attrib_location(ctx->program, 0, "position");
+	ctx->proc_bind_attrib_location(ctx->program, 1, "texture_position");
+
+	ctx->proc_link_program(ctx->program);
+	ctx->proc_get_program_iv(ctx->program, GL_LINK_STATUS, &status);
+	if (status == GL_FALSE) {
+		msg[0] = 0;
+		ctx->proc_get_program_info_log(ctx->program, sizeof(msg),
+								NULL, msg);
+		log_warning("context: cannot link shader: %s\n", msg);
+		ret = -EFAULT;
+		goto err_link;
+	}
+
+	ctx->uni_projection =
+		ctx->proc_get_uniform_location(ctx->program, "projection");
+	ctx->uni_texture =
+		ctx->proc_get_uniform_location(ctx->program, "texture");
+
+	return 0;
+
+err_link:
+	ctx->proc_delete_program(ctx->program);
+	ctx->proc_delete_shader(ctx->fshader);
+err_vshader:
+	ctx->proc_delete_shader(ctx->vshader);
+	return ret;
+}
+
+static void destroy_shader(struct kmscon_context *ctx)
+{
+	if (!ctx)
+		return;
+
+	ctx->proc_delete_program(ctx->program);
+	ctx->proc_delete_shader(ctx->fshader);
+	ctx->proc_delete_shader(ctx->vshader);
+}
+
 /*
  * Create the GL context
  * This uses the EGL library for context creation and needs a valid gbm device
@@ -141,6 +296,36 @@ int kmscon_context_new(struct kmscon_context **out, void *gbm)
 	ctx->proc_delete_framebuffers =
 		(void*) eglGetProcAddress("glDeleteFramebuffers");
 
+	ctx->proc_create_shader =
+		(void*) eglGetProcAddress("glCreateShader");
+	ctx->proc_delete_shader =
+		(void*) eglGetProcAddress("glDeleteShader");
+	ctx->proc_shader_source =
+		(void*) eglGetProcAddress("glShaderSource");
+	ctx->proc_compile_shader =
+		(void*) eglGetProcAddress("glCompileShader");
+	ctx->proc_get_shader_iv =
+		(void*) eglGetProcAddress("glGetShaderiv");
+	ctx->proc_get_shader_info_log =
+		(void*) eglGetProcAddress("glGetShaderInfoLog");
+
+	ctx->proc_create_program =
+		(void*) eglGetProcAddress("glCreateProgram");
+	ctx->proc_delete_program =
+		(void*) eglGetProcAddress("glDeleteProgram");
+	ctx->proc_attach_shader =
+		(void*) eglGetProcAddress("glAttachShader");
+	ctx->proc_bind_attrib_location =
+		(void*) eglGetProcAddress("glBindAttribLocation");
+	ctx->proc_link_program =
+		(void*) eglGetProcAddress("glLinkProgram");
+	ctx->proc_get_program_iv =
+		(void*) eglGetProcAddress("glGetProgramiv");
+	ctx->proc_get_program_info_log =
+		(void*) eglGetProcAddress("glGetProgramInfoLog");
+	ctx->proc_get_uniform_location =
+		(void*) eglGetProcAddress("glGetUniformLocation");
+
 	if (!ctx->proc_rbuf_storage || !ctx->proc_create_image ||
 						!ctx->proc_destroy_image) {
 		log_warning("context: KHR images not supported\n");
@@ -154,6 +339,26 @@ int kmscon_context_new(struct kmscon_context **out, void *gbm)
 		log_warning("context: renderbuffers not supported\n");
 		ret = -ENOTSUP;
 		goto err_free;
+	} else if (!ctx->proc_create_shader ||
+			!ctx->proc_delete_shader ||
+			!ctx->proc_shader_source ||
+			!ctx->proc_compile_shader ||
+			!ctx->proc_get_shader_iv ||
+			!ctx->proc_get_shader_info_log) {
+		log_warning("context: shaders not supported\n");
+		ret = -ENOTSUP;
+		goto err_free;
+	} else if (!ctx->proc_create_program ||
+			!ctx->proc_delete_program ||
+			!ctx->proc_attach_shader ||
+			!ctx->proc_bind_attrib_location ||
+			!ctx->proc_link_program ||
+			!ctx->proc_get_program_iv ||
+			!ctx->proc_get_program_info_log ||
+			!ctx->proc_get_uniform_location) {
+		log_warning("context: shaders not supported\n");
+		ret = -ENOTSUP;
+		goto err_free;
 	}
 
 	ctx->display = eglGetDisplay((EGLNativeDisplayType) gbm);
@@ -191,9 +396,22 @@ int kmscon_context_new(struct kmscon_context **out, void *gbm)
 		goto err_display;
 	}
 
+	if (!eglMakeCurrent(ctx->display, EGL_NO_SURFACE, EGL_NO_SURFACE,
+							ctx->context)) {
+		log_warning("context: cannot use EGL context\n");
+		ret = -EFAULT;
+		goto err_ctx;
+	}
+
+	ret = init_shader(ctx);
+	if (ret)
+		goto err_ctx;
+
 	*out = ctx;
 	return 0;
 
+err_ctx:
+	eglDestroyContext(ctx->display, ctx->context);
 err_display:
 	eglTerminate(ctx->display);
 err_free:
@@ -206,6 +424,7 @@ void kmscon_context_destroy(struct kmscon_context *ctx)
 	if (!ctx)
 		return;
 
+	destroy_shader(ctx);
 	eglDestroyContext(ctx->display, ctx->context);
 	eglTerminate(ctx->display);
 	free(ctx);
diff --git a/src/output_shader.frag b/src/output_shader.frag
new file mode 100644
index 0000000..38be69f
--- /dev/null
+++ b/src/output_shader.frag
@@ -0,0 +1,38 @@
+/*
+ * kmscon - Fragment Shader
+ *
+ * Copyright (c) 2011 David Herrmann <dh.herrmann@googlemail.com>
+ * Copyright (c) 2011 University of Tuebingen
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+/*
+ * Fragement Shader
+ * A basic fragment shader which applies a 2D texture.
+ */
+
+uniform sampler2D texture;
+varying vec2 texpos;
+
+void main()
+{
+	gl_FragColor = texture2D(texture, texpos);
+}
diff --git a/src/output_shader.vert b/src/output_shader.vert
new file mode 100644
index 0000000..2ca0129
--- /dev/null
+++ b/src/output_shader.vert
@@ -0,0 +1,42 @@
+/*
+ * kmscon - Vertex Shader
+ *
+ * Copyright (c) 2011 David Herrmann <dh.herrmann@googlemail.com>
+ * Copyright (c) 2011 University of Tuebingen
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+/*
+ * Vertex Shader
+ * This shader is a very basic vertex shader which forwards all data and
+ * performs basic matrix multiplications.
+ */
+
+uniform mat4 projection;
+attribute vec2 position;
+attribute vec2 texture_position;
+varying vec2 texpos;
+
+void main()
+{
+	gl_Position = projection * vec4(position, 0.0, 1.0);
+	texpos = texture_position;
+}