diff --git a/Makefile b/Makefile
index dc6043e..195aed7 100644
--- a/Makefile
+++ b/Makefile
@@ -18,8 +18,6 @@ CFLAGS += -Wno-error=unused-variable
 CFLAGS += -I$(MAKEFILE_PATH)/include
 CFLAGS += -I$(MAKEFILE_PATH)
 CXXFLAGS += -fno-exceptions
-#CFLAGS += -DDEBUG_BUTTONS
-#CFLAGS += -DDEBUG_AXES
 LDFLAGS += -nostdlib++ -lm -static-libgcc
 ifeq ($(OS),Windows_NT)
 LDFLAGS += -Wl,--subsystem,windows -mwindows
@@ -136,8 +134,11 @@ shaders: $(SHADER_HEADERS)
 
 INPUTS = $(shell find puzzle/ -type f -name input)
 INPUT_OBJS = $(patsubst %,%.o,$(INPUTS))
+INPUT_HEADERS = $(patsubst %,%.h,$(INPUTS))
 
-SOLUTIONS = $(shell find src/solution/2025/ -type f -name '*.c')
+inputs: $(INPUT_HEADERS)
+
+SOLUTIONS = $(shell find src/solution/ -type f -name '*.c')
 SOLUTION_OBJS = $(patsubst %.c,%.o,$(SOLUTIONS))
 
 MAIN_OBJS = \
@@ -150,7 +151,7 @@ MAIN_OBJS = \
 	$(SOLUTION_OBJS) \
 	$(GLFW)
 
-main: $(MAIN_OBJS) | shaders
+main: $(MAIN_OBJS) | shaders inputs
 	$(CXX) $^ $(CXXFLAGS) $(ARCH) -o $@ $(LDFLAGS)
 
 #-include $(shell find -type f -name 'src/*.d')
diff --git a/include/solution/2025/03/solution.fs.glsl.h b/include/solution/2025/03/solution.fs.glsl.h
new file mode 100644
index 0000000..722b1f9
--- /dev/null
+++ b/include/solution/2025/03/solution.fs.glsl.h
@@ -0,0 +1,19 @@
+#pragma once
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern uint32_t _binary_src_solution_2025_03_solution_fs_glsl_start __asm("_binary_src_solution_2025_03_solution_fs_glsl_start");
+extern uint32_t _binary_src_solution_2025_03_solution_fs_glsl_end __asm("_binary_src_solution_2025_03_solution_fs_glsl_end");
+extern uint32_t _binary_src_solution_2025_03_solution_fs_glsl_size __asm("_binary_src_solution_2025_03_solution_fs_glsl_size");
+
+#define src_solution_2025_03_solution_fs_glsl_start ((const char *)&_binary_src_solution_2025_03_solution_fs_glsl_start)
+#define src_solution_2025_03_solution_fs_glsl_end ((const char *)&_binary_src_solution_2025_03_solution_fs_glsl_end)
+#define src_solution_2025_03_solution_fs_glsl_size (src_solution_2025_03_solution_fs_glsl_end - src_solution_2025_03_solution_fs_glsl_start)
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/include/solution/generic.vs.glsl.h b/include/solution/generic.vs.glsl.h
new file mode 100644
index 0000000..6f1461e
--- /dev/null
+++ b/include/solution/generic.vs.glsl.h
@@ -0,0 +1,19 @@
+#pragma once
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern uint32_t _binary_src_solution_generic_vs_glsl_start __asm("_binary_src_solution_generic_vs_glsl_start");
+extern uint32_t _binary_src_solution_generic_vs_glsl_end __asm("_binary_src_solution_generic_vs_glsl_end");
+extern uint32_t _binary_src_solution_generic_vs_glsl_size __asm("_binary_src_solution_generic_vs_glsl_size");
+
+#define src_solution_generic_vs_glsl_start ((const char *)&_binary_src_solution_generic_vs_glsl_start)
+#define src_solution_generic_vs_glsl_end ((const char *)&_binary_src_solution_generic_vs_glsl_end)
+#define src_solution_generic_vs_glsl_size (src_solution_generic_vs_glsl_end - src_solution_generic_vs_glsl_start)
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/puzzle/2025/02/input.h b/puzzle/2025/02/input.h
new file mode 100644
index 0000000..ccca0f7
--- /dev/null
+++ b/puzzle/2025/02/input.h
@@ -0,0 +1,19 @@
+#pragma once
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern uint32_t _binary_puzzle_2025_02_input_start __asm("_binary_puzzle_2025_02_input_start");
+extern uint32_t _binary_puzzle_2025_02_input_end __asm("_binary_puzzle_2025_02_input_end");
+extern uint32_t _binary_puzzle_2025_02_input_size __asm("_binary_puzzle_2025_02_input_size");
+
+#define puzzle_2025_02_input_start ((const char *)&_binary_puzzle_2025_02_input_start)
+#define puzzle_2025_02_input_end ((const char *)&_binary_puzzle_2025_02_input_end)
+#define puzzle_2025_02_input_size (puzzle_2025_02_input_end - puzzle_2025_02_input_start)
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/puzzle/2025/03/input.h b/puzzle/2025/03/input.h
new file mode 100644
index 0000000..abcdf1d
--- /dev/null
+++ b/puzzle/2025/03/input.h
@@ -0,0 +1,19 @@
+#pragma once
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern uint32_t _binary_puzzle_2025_03_input_start __asm("_binary_puzzle_2025_03_input_start");
+extern uint32_t _binary_puzzle_2025_03_input_end __asm("_binary_puzzle_2025_03_input_end");
+extern uint32_t _binary_puzzle_2025_03_input_size __asm("_binary_puzzle_2025_03_input_size");
+
+#define puzzle_2025_03_input_start ((const char *)&_binary_puzzle_2025_03_input_start)
+#define puzzle_2025_03_input_end ((const char *)&_binary_puzzle_2025_03_input_end)
+#define puzzle_2025_03_input_size (puzzle_2025_03_input_end - puzzle_2025_03_input_start)
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/puzzle/2025/04/input.h b/puzzle/2025/04/input.h
new file mode 100644
index 0000000..ea6dfc9
--- /dev/null
+++ b/puzzle/2025/04/input.h
@@ -0,0 +1,19 @@
+#pragma once
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern uint32_t _binary_puzzle_2025_04_input_start __asm("_binary_puzzle_2025_04_input_start");
+extern uint32_t _binary_puzzle_2025_04_input_end __asm("_binary_puzzle_2025_04_input_end");
+extern uint32_t _binary_puzzle_2025_04_input_size __asm("_binary_puzzle_2025_04_input_size");
+
+#define puzzle_2025_04_input_start ((const char *)&_binary_puzzle_2025_04_input_start)
+#define puzzle_2025_04_input_end ((const char *)&_binary_puzzle_2025_04_input_end)
+#define puzzle_2025_04_input_size (puzzle_2025_04_input_end - puzzle_2025_04_input_start)
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/puzzle/2025/05/input.h b/puzzle/2025/05/input.h
new file mode 100644
index 0000000..4bcbfc4
--- /dev/null
+++ b/puzzle/2025/05/input.h
@@ -0,0 +1,19 @@
+#pragma once
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern uint32_t _binary_puzzle_2025_05_input_start __asm("_binary_puzzle_2025_05_input_start");
+extern uint32_t _binary_puzzle_2025_05_input_end __asm("_binary_puzzle_2025_05_input_end");
+extern uint32_t _binary_puzzle_2025_05_input_size __asm("_binary_puzzle_2025_05_input_size");
+
+#define puzzle_2025_05_input_start ((const char *)&_binary_puzzle_2025_05_input_start)
+#define puzzle_2025_05_input_end ((const char *)&_binary_puzzle_2025_05_input_end)
+#define puzzle_2025_05_input_size (puzzle_2025_05_input_end - puzzle_2025_05_input_start)
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/puzzle/2025/06/input.h b/puzzle/2025/06/input.h
new file mode 100644
index 0000000..d419a18
--- /dev/null
+++ b/puzzle/2025/06/input.h
@@ -0,0 +1,19 @@
+#pragma once
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern uint32_t _binary_puzzle_2025_06_input_start __asm("_binary_puzzle_2025_06_input_start");
+extern uint32_t _binary_puzzle_2025_06_input_end __asm("_binary_puzzle_2025_06_input_end");
+extern uint32_t _binary_puzzle_2025_06_input_size __asm("_binary_puzzle_2025_06_input_size");
+
+#define puzzle_2025_06_input_start ((const char *)&_binary_puzzle_2025_06_input_start)
+#define puzzle_2025_06_input_end ((const char *)&_binary_puzzle_2025_06_input_end)
+#define puzzle_2025_06_input_size (puzzle_2025_06_input_end - puzzle_2025_06_input_start)
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/puzzle/2025/07/input.h b/puzzle/2025/07/input.h
new file mode 100644
index 0000000..6d17278
--- /dev/null
+++ b/puzzle/2025/07/input.h
@@ -0,0 +1,19 @@
+#pragma once
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern uint32_t _binary_puzzle_2025_07_input_start __asm("_binary_puzzle_2025_07_input_start");
+extern uint32_t _binary_puzzle_2025_07_input_end __asm("_binary_puzzle_2025_07_input_end");
+extern uint32_t _binary_puzzle_2025_07_input_size __asm("_binary_puzzle_2025_07_input_size");
+
+#define puzzle_2025_07_input_start ((const char *)&_binary_puzzle_2025_07_input_start)
+#define puzzle_2025_07_input_end ((const char *)&_binary_puzzle_2025_07_input_end)
+#define puzzle_2025_07_input_size (puzzle_2025_07_input_end - puzzle_2025_07_input_start)
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/main.c b/src/main.c
index 9e243ad..1ff091d 100644
--- a/src/main.c
+++ b/src/main.c
@@ -28,6 +28,7 @@ const float triangle_array[] = {
 };
 
 extern void solution_2025_01(unsigned int vertex_array);
+extern void solution_2025_03(unsigned int vertex_array);
 
 int main()
 {
@@ -86,7 +87,8 @@ int main()
     if(glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
       glfwSetWindowShouldClose(window, true);
 
-    solution_2025_01(vertex_array);
+    //solution_2025_01(vertex_array);
+    solution_2025_03(vertex_array);
 
     break;
 
diff --git a/src/solution/2025/01/solution.c b/src/solution/2025/01/solution.c
index f44e155..8d1feaf 100644
--- a/src/solution/2025/01/solution.c
+++ b/src/solution/2025/01/solution.c
@@ -5,11 +5,11 @@
 #include "opengl.h"
 
 #include "puzzle/2025/01/input.h"
-#include "solution/2025/01/solution.vs.glsl.h"
+#include "solution/generic.vs.glsl.h"
 #include "solution/2025/01/solution.fs.glsl.h"
 
-const int output_width = 1;
-const int output_height = 1;
+static const int output_width = 1;
+static const int output_height = 1;
 
 void solution_2025_01(unsigned int vertex_array)
 {
@@ -38,8 +38,8 @@ void solution_2025_01(unsigned int vertex_array)
   // shaders
   //////////////////////////////////////////////////////////////////////
 
-  uint program = compile_shader(src_solution_2025_01_solution_vs_glsl_start,
-                                src_solution_2025_01_solution_vs_glsl_size,
+  uint program = compile_shader(src_solution_generic_vs_glsl_start,
+                                src_solution_generic_vs_glsl_size,
                                 src_solution_2025_01_solution_fs_glsl_start,
                                 src_solution_2025_01_solution_fs_glsl_size);
   uint program__input_sampler = glGetUniformLocation(program, "input_sampler");
diff --git a/src/solution/2025/03/parse_input.fs.glsl b/src/solution/2025/03/parse_input.fs.glsl
index 7fd4633..fec9d31 100644
--- a/src/solution/2025/03/parse_input.fs.glsl
+++ b/src/solution/2025/03/parse_input.fs.glsl
@@ -1,34 +1,68 @@
 #version 330 core
 
-uniform vec4 in_size; // w h halfpx_w halfpx_h
-uniform vec4 out_size; // w h halfpx_w halfpx_h
+uniform sampler2D input_sampler;
+uniform vec4 input_dim; // w h halfpx_w halfpx_h
+uniform float input_length;
+
+uniform vec4 output_dim; // w h halfpx_w halfpx_h
 
 out vec4 fragment_result;
 
 in vec2 f_position;
 
-vec2 halfpixel(float x, float y, vec4 size)
+vec2 halfpixel(float x, float y, vec4 dim)
 {
-  return vec2((x * 2.0 + 1) * size.z,
-              (y * 2.0 + 1) * size.w);
+  return vec2((x * 2.0 + 1.0) * dim.z,
+              (y * 2.0 + 1.0) * dim.w);
 }
 
-vec2 rectangularize(float ix, vec4 size)
+vec2 rectangularize(float ix, vec4 dim)
 {
-  float y = floor(ix * size.z * 2.0);
-  float x = ix - size.x * y;
+  float y = floor(ix * dim.z * 2.0);
+  float x = ix - dim.x * y;
 
-  return halfpixel(x, y, size);
+  return halfpixel(x, y, dim);
 }
 
 float get_input(float ix)
 {
-  return texture(tex_sampler, rectangularize(ix, in_size)).x * 255.0;
+  return texture(input_sampler, rectangularize(ix, input_dim)).x * 255.0;
 }
 
-void main()
+vec2 integer_coord(vec2 v, vec4 dim)
+{
+  return ((v * 0.5 + 0.5) - dim.zw) * dim.xy;
+}
+
+const float ascii_newline = 10.0;
+const float ascii_zero = 48.0;
+
+float find_character(vec2 v)
 {
   float x = 0.0;
   float y = 0.0;
   float ix = 0.0;
+
+  while (ix < input_length) {
+    float c = get_input(ix);
+    if (x == v.x && y == v.y)
+      return c - ascii_zero;
+    if (c == ascii_newline) {
+      x = 0.0;
+      y += 1.0;
+    } else {
+      x += 1.0;
+    }
+    ix += 1.0;
+  }
+
+  return -1.0;
+}
+
+void main()
+{
+  vec2 v = integer_coord(f_position, output_dim);
+
+  //fragment_result = vec4(v, 0, 0);
+  fragment_result = vec4(find_character(v));
 }
diff --git a/src/solution/2025/03/solution.c b/src/solution/2025/03/solution.c
new file mode 100644
index 0000000..c46df61
--- /dev/null
+++ b/src/solution/2025/03/solution.c
@@ -0,0 +1,164 @@
+#include <stdio.h>
+
+#include "glad.h"
+#include "input.h"
+#include "opengl.h"
+
+#include "puzzle/2025/03/input.h"
+#include "solution/generic.vs.glsl.h"
+#include "solution/2025/03/parse_input.fs.glsl.h"
+#include "solution/2025/03/solution.fs.glsl.h"
+
+static const int output_width = 1;
+static const int output_height = 1;
+
+static const int parsed_input_width = 128;
+static const int parsed_input_height = 256;
+
+void solution_2025_03(unsigned int vertex_array)
+{
+  //////////////////////////////////////////////////////////////////////
+  // textures
+  //////////////////////////////////////////////////////////////////////
+
+  const char * input_start = puzzle_2025_03_input_start;
+  const int input_length = puzzle_2025_03_input_size;
+  int input_width;
+  uint texture_input = rectangularize_input(input_start,
+                                            input_length,
+                                            &input_width);
+  int input_height = input_width;
+
+  uint texture_parsed_input = make_texture(NULL,
+                                           GL_R32F,
+                                           parsed_input_width,
+                                           parsed_input_height,
+                                           GL_RED,
+                                           GL_UNSIGNED_BYTE);
+  uint framebuffer_parsed_input = make_framebuffer(&texture_parsed_input, 1);
+
+
+  uint texture_output = make_texture(NULL,
+                                     GL_RGB32F,
+                                     output_width,
+                                     output_height,
+                                     GL_RGB,
+                                     GL_UNSIGNED_BYTE);
+  uint framebuffer_output = make_framebuffer(&texture_output, 1);
+
+  //////////////////////////////////////////////////////////////////////
+  // shaders
+  //////////////////////////////////////////////////////////////////////
+
+  uint p__parse_input = compile_shader(src_solution_generic_vs_glsl_start,
+                                       src_solution_generic_vs_glsl_size,
+                                       src_solution_2025_03_parse_input_fs_glsl_start,
+                                       src_solution_2025_03_parse_input_fs_glsl_size);
+  uint p__parse_input__input_sampler = glGetUniformLocation(p__parse_input, "input_sampler");
+  uint p__parse_input__input_dim = glGetUniformLocation(p__parse_input, "input_dim");
+  uint p__parse_input__input_length = glGetUniformLocation(p__parse_input, "input_length");
+  uint p__parse_input__output_dim = glGetUniformLocation(p__parse_input, "output_dim");
+
+  uint p__solution = compile_shader(src_solution_generic_vs_glsl_start,
+                                    src_solution_generic_vs_glsl_size,
+                                    src_solution_2025_03_solution_fs_glsl_start,
+                                    src_solution_2025_03_solution_fs_glsl_size);
+  uint p__solution__input_sampler = glGetUniformLocation(p__solution, "input_sampler");
+  uint p__solution__input_dim = glGetUniformLocation(p__solution, "input_dim");
+  uint p__solution__input_length = glGetUniformLocation(p__solution, "input_length");
+
+  //////////////////////////////////////////////////////////////////////
+  // runner step 1: parse input
+  //////////////////////////////////////////////////////////////////////
+
+  // shader uniforms
+
+  glUseProgram(p__parse_input);
+  glUniform1i(p__parse_input__input_sampler, 0);
+  glUniform4f(p__parse_input__input_dim,
+              input_width,
+              input_height,
+              0.5f / input_width,
+              0.5f / input_height);
+  glUniform1f(p__parse_input__input_length, input_length);
+
+  glUniform4f(p__parse_input__output_dim,
+              parsed_input_width,
+              parsed_input_height,
+              0.5f / parsed_input_width,
+              0.5f / parsed_input_height);
+
+  // draw
+
+  glBindFramebuffer(GL_FRAMEBUFFER, framebuffer_parsed_input);
+  glViewport(0, 0, parsed_input_width, parsed_input_height);
+
+  glActiveTexture(GL_TEXTURE0);
+  glBindTexture(GL_TEXTURE_2D, texture_input);
+  const uint draw_buffers0[1] = {GL_COLOR_ATTACHMENT0};
+  glDrawBuffers(1, draw_buffers0);
+
+  glBindVertexArray(vertex_array);
+  glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+
+  // debug
+
+  if (1) {
+    float out[1 * parsed_input_width * parsed_input_height] = {};
+    glReadPixels(0, 0,
+                 parsed_input_width, parsed_input_height,
+                 GL_RED,
+                 GL_FLOAT,
+                 out);
+
+    for (int y = 0; y < parsed_input_height; y++) {
+      for (int x = 0; x < parsed_input_width; x++) {
+        printf("%d", (int)out[(y * parsed_input_width + x) * 1 + 0]);
+      }
+      printf("\n");
+      break;
+    }
+  }
+
+  //////////////////////////////////////////////////////////////////////
+  // runner step 2: solve
+  //////////////////////////////////////////////////////////////////////
+
+  // shader uniforms
+
+  glUseProgram(p__solution);
+  glUniform1i(p__solution__input_sampler, 0);
+  glUniform4f(p__solution__input_dim,
+              parsed_input_width,
+              parsed_input_height,
+              0.5f / parsed_input_width,
+              0.5f / parsed_input_height);
+  glUniform2f(p__solution__input_length,
+              100,
+              200); // is this cheating?
+
+  // draw
+
+  glBindFramebuffer(GL_FRAMEBUFFER, framebuffer_output);
+  glViewport(0, 0, output_width, output_height);
+
+  glActiveTexture(GL_TEXTURE0);
+  glBindTexture(GL_TEXTURE_2D, texture_parsed_input);
+  const uint draw_buffers1[1] = {GL_COLOR_ATTACHMENT0};
+  glDrawBuffers(1, draw_buffers1);
+
+  glBindVertexArray(vertex_array);
+  glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+
+  //////////////////////////////////////////////////////////////////////
+  // output
+  //////////////////////////////////////////////////////////////////////
+
+  float out[3 * output_width * output_height] = {};
+  glReadPixels(0, 0,
+               output_width, output_height,
+               GL_RGB,
+               GL_FLOAT,
+               out);
+  printf("2025/03: %2.3f %2.3f\n", out[0], (double)out[1] * 16777216.0 + (double)out[2]);
+}
diff --git a/src/solution/2025/03/solution.fs.glsl b/src/solution/2025/03/solution.fs.glsl
new file mode 100644
index 0000000..2bce4f9
--- /dev/null
+++ b/src/solution/2025/03/solution.fs.glsl
@@ -0,0 +1,78 @@
+#version 330 core
+
+uniform sampler2D input_sampler;
+uniform vec4 input_dim; // w h halfpx_w halfpx_h
+
+uniform vec2 input_length;
+
+out vec4 fragment_result;
+
+vec2 halfpixel(float x, float y, vec4 dim)
+{
+  return vec2((x * 2.0 + 1.0) * dim.z,
+              (y * 2.0 + 1.0) * dim.w);
+}
+
+float get_input(float x, float y)
+{
+  return texture(input_sampler, halfpixel(x, y, input_dim)).x;
+}
+
+vec2 max_single(float y, float start, float end)
+{
+  float max_v = get_input(start, y);
+  float max_ix = start;
+  float x = max_ix + 1.0;
+  while (x < end) {
+    float value = get_input(x, y);
+    if (value > max_v) {
+      max_v = value;
+      max_ix = x;
+    }
+    x += 1.0;
+  }
+  return vec2(max_v, max_ix);
+}
+
+double powd(float n)
+{
+  double res = double(1.0);
+  for (float i = 0.0; i < n; i++) {
+    res *= double(10.0);
+  }
+  return res;
+}
+
+double max_joltage_n(float y, float reserve)
+{
+  float start = 0.0;
+  double acc = double(0.0);
+  while (reserve > 0.0) {
+    reserve -= 1.0;
+    vec2 res = max_single(y, start, input_length.x - reserve);
+    float d = res.x;
+    float ix = res.y;
+    start = ix + 1.0;
+    acc += powd(reserve) * double(d);
+  }
+  return acc;
+}
+
+void main()
+{
+  double acc_part1 = double(0.0);
+  for (float i = 0.0; i < input_length.y; i += 1.0) {
+    acc_part1 += max_joltage_n(i, 2);
+  }
+
+  double acc_part2 = double(0.0);
+  for (float i = 0.0; i < input_length.y; i += 1.0) {
+    acc_part2 += max_joltage_n(i, 12);
+  }
+
+  double radix = double(16777216.0);
+  double h = double(floor(float(acc_part2 / radix)));
+  double l = acc_part2 - h * radix;
+
+  fragment_result = vec4(float(acc_part1), h, l, 0);
+}
diff --git a/src/solution/2025/01/solution.vs.glsl b/src/solution/generic.vs.glsl
similarity index 70%
rename from src/solution/2025/01/solution.vs.glsl
rename to src/solution/generic.vs.glsl
index cdcb557..e1b1518 100644
--- a/src/solution/2025/01/solution.vs.glsl
+++ b/src/solution/generic.vs.glsl
@@ -2,7 +2,11 @@
 
 layout (location = 0) in vec2 position;
 
+out vec2 f_position;
+
 void main()
 {
+  f_position = position;
+
   gl_Position = vec4(position, 0, 1);
 }